code: public function injectLogger(bool $flag = null) : bool
      {
          if (null === $flag) { return $this->injectLogger; }
  
          $this->injectLogger = $flag;
          return $flag;
      }
docs: Set or get the injectLogger flag
  
  If called with an argument, sets the flag accordingly and returns
  it.
  
  @param bool|null $flag
  @return bool