original_string: public function getHeader($key = null, $toLower = true)
      {
          if ($key === null) {
              return $this->_headers;
          }
          if ($toLower === true) {
              $key = strtolower($key);
          }
          return isset($this->_headers[$key]) ? $this->_headers[$key] : null;
      }
code: public function getHeader($key = null, $toLower = true)
      {
          if ($key === null) {
              return $this->_headers;
          }
          if ($toLower === true) {
              $key = strtolower($key);
          }
          return isset($this->_headers[$key]) ? $this->_headers[$key] : null;
      }
code_tokens: public function getHeader ( $ key = null , $ toLower = true ) { if ( $ key === null ) { return $ this -> _headers ; } if ( $ toLower === true ) { $ key = strtolower ( $ key ) ; } return isset ( $ this -> _headers [ $ key ] ) ? $ this -> _headers [ $ key ] : null ; }
docstring: Get a http header or all http headers
  @param mixed $key the header key to be got, or null to get all headers
  @param boolean $toLower convert key to lowercase
  @return array|string the header value, or headers array when key is null.
docstring_tokens: Get a http header or all http headers