original_string: public function checkMapper(string $mapper): bool
      {
          if (!isset($this->$mapper)) {
              Schematic::error('Mapper '.$mapper.' not found');
  
              return false;
          }
          if (!$this->$mapper instanceof MapperInterface) {
              Schematic::error(get_class($this->$mapper).' does not implement MapperInterface');
  
              return false;
          }
  
          return true;
      }
code: public function checkMapper(string $mapper): bool
      {
          if (!isset($this->$mapper)) {
              Schematic::error('Mapper '.$mapper.' not found');
  
              return false;
          }
          if (!$this->$mapper instanceof MapperInterface) {
              Schematic::error(get_class($this->$mapper).' does not implement MapperInterface');
  
              return false;
          }
  
          return true;
      }
code_tokens: public function checkMapper ( string $ mapper ) : bool { if ( ! isset ( $ this -> $ mapper ) ) { Schematic :: error ( 'Mapper ' . $ mapper . ' not found' ) ; return false ; } if ( ! $ this -> $ mapper instanceof MapperInterface ) { Schematic :: error ( get_class ( $ this -> $ mapper ) . ' does not implement MapperInterface' ) ; return false ; } return true ; }
docstring: Check mapper handle is valid.
  
  @param string $mapper
  
  @return bool
docstring_tokens: Check mapper handle is valid .