code: def get_concrete_derived_from(self, address):
      
      current_address = address
      next_address = self._derived_from_by_derivative.get(current_address, current_address)
      while next_address != current_address:
        current_address = next_address
        next_address = self._derived_from_by_derivative.get(current_address, current_address)
      return self.get_target(current_address)
docs: Get the concrete target the specified target was (directly or indirectly) derived from.
  
      The returned target is guaranteed to not have been derived from any other target.
  
      :API: public