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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(self, count=1):
 """ Inserts lines at line with cursor. Lines displayed below cursor move down. Lines moved past the bottom margin are lost. """

        trimmed = self.display[:self.y+1] + \
                  [u" " * self.size[1]] * count + \
                  self.display[self.y+1:self.y+count+1]
        self.display = trimmed[:self.size[0]]