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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 is_valid_complex_fault_mesh_spacing(self):
 """ The `complex_fault_mesh_spacing` parameter can be None only if `rupture_mesh_spacing` is set. In that case it is identified with it. """

        rms = getattr(self, 'rupture_mesh_spacing', None)
        if rms and not getattr(self, 'complex_fault_mesh_spacing', None):
            self.complex_fault_mesh_spacing = self.rupture_mesh_spacing
        return True