public function clearHeader($headerName)
    {
        if (isset($this->_headers[$headerName])){
            unset($this->_headers[$headerName]);
        }
        return $this;
    }
public function clearHeader($headerName)
    {
        if (isset($this->_headers[$headerName])){
            unset($this->_headers[$headerName]);
        }
        return $this;
    }
public function clearHeader ( $ headerName ) { if ( isset ( $ this -> _headers [ $ headerName ] ) ) { unset ( $ this -> _headers [ $ headerName ] ) ; } return $ this ; }
Clear header from the message

@param string $headerName
@return Zend_Mail Provides fluent inter
Clear header from the message