original_string: public function clearHeader($headerName)
      {
          if (isset($this->_headers[$headerName])){
              unset($this->_headers[$headerName]);
          }
          return $this;
      }
code: public function clearHeader($headerName)
      {
          if (isset($this->_headers[$headerName])){
              unset($this->_headers[$headerName]);
          }
          return $this;
      }
code_tokens: public function clearHeader ( $ headerName ) { if ( isset ( $ this -> _headers [ $ headerName ] ) ) { unset ( $ this -> _headers [ $ headerName ] ) ; } return $ this ; }
docstring: Clear header from the message
  
  @param string $headerName
  @return Zend_Mail Provides fluent inter
docstring_tokens: Clear header from the message