original_string: public function addHeader($key, $value) {
  
  		if(false === is_string($key)) {
  			return trigger_error(sprintf('Argument 1 passed to %s() must be of the type string, "%s" given', __METHOD__, gettype($key)), E_USER_ERROR);
  		}
  
  		if(false === is_string($value)) {
  			return trigger_error(sprintf('Argument 2 passed to %s() must be of the type string, "%s" given', __METHOD__, gettype($value)), E_USER_ERROR);
  		}
  
  		if(false === isset($this -> headers['custom'])) {
  			$this -> headers['custom'] = [];
  		}
  
  		$this -> headers['custom'][$key] = $value;
  	}
code: public function addHeader($key, $value) {
  
  		if(false === is_string($key)) {
  			return trigger_error(sprintf('Argument 1 passed to %s() must be of the type string, "%s" given', __METHOD__, gettype($key)), E_USER_ERROR);
  		}
  
  		if(false === is_string($value)) {
  			return trigger_error(sprintf('Argument 2 passed to %s() must be of the type string, "%s" given', __METHOD__, gettype($value)), E_USER_ERROR);
  		}
  
  		if(false === isset($this -> headers['custom'])) {
  			$this -> headers['custom'] = [];
  		}
  
  		$this -> headers['custom'][$key] = $value;
  	}
code_tokens: public function addHeader ( $ key , $ value ) { if ( false === is_string ( $ key ) ) { return trigger_error ( sprintf ( 'Argument 1 passed to %s() must be of the type string, "%s" given' , __METHOD__ , gettype ( $ key ) ) , E_USER_ERROR ) ; } if ( false === is_string ( $ value ) ) { return trigger_error ( sprintf ( 'Argument 2 passed to %s() must be of the type string, "%s" given' , __METHOD__ , gettype ( $ value ) ) , E_USER_ERROR ) ; } if ( false === isset ( $ this -> headers [ 'custom' ] ) ) { $ this -> headers [ 'custom' ] = [ ] ; } $ this -> headers [ 'custom' ] [ $ key ] = $ value ; }
docstring: Adds a custom header to the mail
  @param string $key
  @param string $value
  @return sFire\Mail\Mail
docstring_tokens: Adds a custom header to the mail