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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 change_last_time_step(self, **replace_time_step_kwargs):
 """Replace the last time-steps with the given kwargs."""


    # Pre-conditions: self._time_steps shouldn't be empty.
    assert self._time_steps
    self._time_steps[-1] = self._time_steps[-1].replace(
        **replace_time_step_kwargs)