<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def insert_after(self, text):
 """ Create a new document, with this text inserted after the buffer. It keeps selection ranges and cursor position in sync. """

        return Document(
                text=self.text + text,
                cursor_position=self.cursor_position,
                selection=self.selection)