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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def insert_line_below(self, copy_margin=True):
 """ Insert a new line below the current one. """

        if copy_margin:
            insert = '\n' + self.document.leading_whitespace_in_current_line
        else:
            insert = '\n'

        self.cursor_position += self.document.get_end_of_line_position()
        self.insert_text(insert)