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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 occupations( self, site_label ):
 """ Number of these atoms occupying a specific site type. Args: site_label (Str):
 Label for the site type being considered. Returns: (Int):
 Number of atoms occupying sites of type `site_label`. """

        return sum( atom.site.label == site_label for atom in self.atoms )