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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_filename_by_class(self, current_class):
 """ Returns the filename of the DEX file where the class is in. Returns the first filename this class was present. For example, if you analyzed an APK, this should return the filename of the APK and not of the DEX file. :param current_class: ClassDefItem :returns: None if class was not found or the filename """

        for digest, dx in self.analyzed_vms.items():
            if dx.is_class_present(current_class.get_name()):
                return self.analyzed_digest[digest]
        return None