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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 next_session_label(self, session_label):
 """ Given a session label, returns the label of the next session. Parameters session_label: pd.Timestamp A session whose next session is desired. Returns ------- pd.Timestamp The next session label (midnight UTC). Notes ----- Raises ValueError if the given session is the last session in this calendar. """

        idx = self.schedule.index.get_loc(session_label)
        try:
            return self.schedule.index[idx + 1]
        except IndexError:
            if idx == len(self.schedule.index) - 1:
                raise ValueError("There is no next session as this is the end"
                                 " of the exchange calendar.")
            else:
                raise