| @@ -87,6 +87,6 @@ | ||
| 87 | 87 | */ | 
| 88 | 88 | public function __toString(): string | 
| 89 | 89 |      { | 
| 90 | -        return "(" . $this->sourceVertex + " : " + $this->targetVertex + ")"; | |
| 90 | +        return "(" . $this->sourceVertex + " : " +$this->targetVertex + ")"; | |
| 91 | 91 | } | 
| 92 | 92 | } | 
| @@ -207,7 +207,7 @@ | ||
| 207 | 207 |          } elseif ($vertex->equals($target)) { | 
| 208 | 208 | return $source; | 
| 209 | 209 |          } else { | 
| 210 | -            throw new InvalidArgumentException("no such vertex: " + $vertex); | |
| 210 | +            throw new InvalidArgumentException("no such vertex: " +$vertex); | |
| 211 | 211 | } | 
| 212 | 212 | } | 
| 213 | 213 | |