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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 coincidents(self):
 """ return the a list of coincident sites. """

        coincident_sites = []
        for i, tag in enumerate(self.site_properties['grain_label']):
            if 'incident' in tag:
                coincident_sites.append(self.sites[i])
        return coincident_sites