public function trim($characters = null)
    {
        $this->string = trim($this->string, $characters);
        return $this;
    }
public function trim($characters = null)
    {
        $this->string = trim($this->string, $characters);
        return $this;
    }
public function trim ( $ characters = null ) { $ this -> string = trim ( $ this -> string , $ characters ) ; return $ this ; }
Trim characters from the left and right side of this sequence.

@param string|null $characters The characters to trim. Leave empty for whitespaces.

@return StringBuilder
Trim characters from the left and right side of this sequence .