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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 get_transition_chempots(self, element):
 """ Get the critical chemical potentials for an element in the Phase Diagram. Args: element: An element. Has to be in the PD in the first place. Returns: A sorted sequence of critical chemical potentials, from less negative to more negative. """

        if element not in self.elements:
            raise ValueError("get_transition_chempots can only be called with "
                             "elements in the phase diagram.")

        critical_chempots = []
        for facet in self.facets:
            chempots = self._get_facet_chempots(facet)
            critical_chempots.append(chempots[element])

        clean_pots = []
        for c in sorted(critical_chempots):
            if len(clean_pots) == 0:
                clean_pots.append(c)
            else:
                if abs(c - clean_pots[-1]) > PhaseDiagram.numerical_tol:
                    clean_pots.append(c)
        clean_pots.reverse()
        return tuple(clean_pots)