Write docstring to editor at mouse position.

def write_docstring_at_first_line_of_function(self):
        """Write docstring to editor at mouse position."""
        result = self.get_function_definition_from_first_line()
        editor = self.code_editor
        if result:
            func_text, number_of_line_func = result
            line_number_function = (self.line_number_cursor +
                                    number_of_line_func - 1)

            cursor = editor.textCursor()
            line_number_cursor = cursor.blockNumber() + 1
            offset = line_number_function - line_number_cursor
            if offset > 0:
                for __ in range(offset):
                    cursor.movePosition(QTextCursor.NextBlock)
            else:
                for __ in range(abs(offset)):
                    cursor.movePosition(QTextCursor.PreviousBlock)
            cursor.movePosition(QTextCursor.EndOfLine, QTextCursor.MoveAnchor)
            editor.setTextCursor(cursor)

            indent = get_indent(func_text)
            editor.insert_text('\n{}{}"""'.format(indent, editor.indent_chars))
            self.write_docstring()