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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 set_display_label(self, display_label):
 """Seta a display label. arg: display_label (string):
 the new display label raise: InvalidArgument - ``display_label`` is invalid raise: NoAccess - ``display_label`` cannot be modified raise: NullArgument - ``display_label`` is ``null`` *compliance: mandatory -- This method must be implemented.* """

        if self.get_display_label_metadata().is_read_only():
            raise errors.NoAccess()
        if not self._is_valid_string(display_label,
                                     self.get_display_label_metadata()):
            raise errors.InvalidArgument()
        self._my_map['displayLabel']['text'] = display_label