code: def get_digest_by_class(self, current_class):
          
          for digest, dx in self.analyzed_vms.items():
              if dx.is_class_present(current_class.get_name()):
                  return digest
          return None
docs: Return the SHA256 hash of the object containing the ClassDefItem
  
          Returns the first digest this class was present.
          For example, if you analyzed an APK, this should return the digest of
          the APK and not of the DEX file.