def _union_with_dsis(self, dsis):
copied = self.copy()<EOL>for a in dsis._si_set:<EOL><INDENT>copied = copied.union(a)<EOL><DEDENT>if isinstance(copied, DiscreteStridedIntervalSet):<EOL><INDENT>copied._update_bounds(dsis)<EOL><DEDENT>return copied.normalize()<EOL>
Union with another DiscreteStridedIntervalSet.

:param dsis:
:return: