Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like Builder often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Builder, and based on these observations, apply Extract Interface, too.
1 | <?php |
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31 | class Builder extends \Doctrine\MongoDB\Query\Builder |
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32 | { |
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33 | /** |
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34 | * The DocumentManager instance for this query |
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35 | * |
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36 | * @var DocumentManager |
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37 | */ |
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38 | private $dm; |
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39 | |||
40 | /** |
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41 | * The ClassMetadata instance. |
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42 | * |
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43 | * @var \Doctrine\ODM\MongoDB\Mapping\ClassMetadata |
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44 | */ |
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45 | private $class; |
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46 | |||
47 | /** |
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48 | * The current field we are operating on. |
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49 | * |
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50 | * @todo Change this to private once ODM requires doctrine/mongodb 1.1+ |
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51 | * @var string |
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52 | */ |
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53 | protected $currentField; |
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54 | |||
55 | /** |
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56 | * Whether or not to hydrate the data to documents. |
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57 | * |
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58 | * @var boolean |
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59 | */ |
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60 | private $hydrate = true; |
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61 | |||
62 | /** |
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63 | * Whether or not to refresh the data for documents that are already in the identity map. |
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64 | * |
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65 | * @var boolean |
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66 | */ |
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67 | private $refresh = false; |
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68 | |||
69 | /** |
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70 | * Array of primer Closure instances. |
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71 | * |
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72 | * @var array |
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73 | */ |
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74 | private $primers = array(); |
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75 | |||
76 | /** |
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77 | * Whether or not to require indexes. |
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78 | * |
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79 | * @var bool |
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80 | */ |
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81 | private $requireIndexes; |
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82 | |||
83 | /** |
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84 | * Whether or not to register documents in UnitOfWork. |
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85 | * |
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86 | * @var bool |
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87 | */ |
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88 | private $readOnly; |
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89 | |||
90 | /** |
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91 | * Construct a Builder |
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92 | * |
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93 | * @param DocumentManager $dm |
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94 | * @param string[]|string|null $documentName (optional) an array of document names, the document name, or none |
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95 | */ |
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96 | 221 | public function __construct(DocumentManager $dm, $documentName = null) |
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104 | |||
105 | /** |
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106 | * Set whether or not to require indexes. |
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107 | * |
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108 | * @param bool $requireIndexes |
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109 | * @return $this |
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110 | */ |
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111 | 2 | public function requireIndexes($requireIndexes = true) |
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116 | |||
117 | /** |
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118 | * Set the current field to operate on. |
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119 | * |
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120 | * @param string $field |
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121 | * @return $this |
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122 | */ |
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123 | 141 | public function field($field) |
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130 | |||
131 | /** |
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132 | * Use a primer to eagerly load all references in the current field. |
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133 | * |
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134 | * If $primer is true or a callable is provided, referenced documents for |
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135 | * this field will loaded into UnitOfWork immediately after the query is |
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136 | * executed. This will avoid multiple queries due to lazy initialization of |
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137 | * Proxy objects. |
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138 | * |
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139 | * If $primer is false, no priming will take place. That is also the default |
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140 | * behavior. |
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141 | * |
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142 | * If a custom callable is used, its signature should conform to the default |
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143 | * Closure defined in {@link ReferencePrimer::__construct()}. |
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144 | * |
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145 | * @param boolean|callable $primer |
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146 | * @return $this |
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147 | * @throws \InvalidArgumentException If $primer is not boolean or callable |
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148 | */ |
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149 | 22 | public function prime($primer = true) |
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168 | |||
169 | /** |
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170 | * {@inheritdoc} |
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171 | */ |
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172 | 5 | public function eagerCursor($bool = true) |
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180 | |||
181 | |||
182 | /** |
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183 | * @param bool $bool |
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184 | * @return $this |
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185 | */ |
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186 | 16 | public function hydrate($bool = true) |
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191 | |||
192 | /** |
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193 | * @param bool $bool |
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194 | * @return $this |
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195 | */ |
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196 | 1 | public function readOnly($bool = true) |
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201 | |||
202 | /** |
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203 | * @param bool $bool |
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204 | * @return $this |
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205 | */ |
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206 | 5 | public function refresh($bool = true) |
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211 | |||
212 | /** |
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213 | * Change the query type to find and optionally set and change the class being queried. |
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214 | * |
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215 | * @param string $documentName |
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216 | * @return $this |
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217 | */ |
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218 | 12 | public function find($documentName = null) |
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225 | |||
226 | /** |
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227 | * @param string $documentName |
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228 | * @return $this |
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229 | */ |
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230 | 7 | public function findAndUpdate($documentName = null) |
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237 | |||
238 | /** |
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239 | * @param bool $bool |
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240 | * @return $this |
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241 | */ |
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242 | 4 | public function returnNew($bool = true) |
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249 | |||
250 | /** |
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251 | * @param string $documentName |
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252 | * @return $this |
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253 | */ |
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254 | 1 | public function findAndRemove($documentName = null) |
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261 | |||
262 | /** |
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263 | * @param string $documentName |
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264 | * @return $this |
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265 | */ |
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266 | 12 | public function update($documentName = null) |
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273 | |||
274 | /** |
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275 | * @param string $documentName |
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276 | * @return $this |
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277 | */ |
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278 | 1 | public function insert($documentName = null) |
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285 | |||
286 | /** |
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287 | * @param string $documentName |
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288 | * @return $this |
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289 | */ |
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290 | 1 | public function remove($documentName = null) |
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297 | |||
298 | /** |
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299 | * @param object $document |
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300 | * @return $this |
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301 | */ |
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302 | 10 | public function references($document) |
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307 | |||
308 | /** |
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309 | * @param object $document |
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310 | * @return $this |
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311 | */ |
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312 | 7 | public function includesReferenceTo($document) |
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317 | |||
318 | /** |
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319 | * Gets the Query executable. |
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320 | * |
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321 | * @param array $options |
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322 | * @return Query $query |
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323 | */ |
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324 | 190 | public function getQuery(array $options = array()) |
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382 | |||
383 | /** |
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384 | * Create a new Expr instance that can be used as an expression with the Builder |
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385 | * |
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386 | * @return Expr $expr |
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387 | */ |
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388 | 25 | public function expr() |
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395 | |||
396 | /** |
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397 | * @param string[]|string $documentName an array of document names or just one. |
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398 | */ |
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399 | 220 | private function setDocumentName($documentName) |
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425 | |||
426 | /** |
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427 | * Get Discriminator Values |
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428 | * |
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429 | * @param \Iterator|array $classNames |
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430 | * @return array an array of discriminatorValues (mixed type) |
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431 | * @throws \InvalidArgumentException if the number of found collections > 1 |
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432 | */ |
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433 | 2 | private function getDiscriminatorValues($classNames) |
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448 | } |
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449 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different sub-classes of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the parent class: