Return the active configurations.

def register_or_check(klass, finish, mean, between, refresh_presision, configuration):
		"""Return the active configurations."""
		m, created = klass.objects.get_or_create(finish=finish, configuration=configuration)
		if created:
			m.mean=mean
			m.between=between
			m.refresh_presision=refresh_presision
			m.save()
		else:
			diff = abs(float(m.mean) - mean)
			if not(diff < 0.006 and m.between == between and m.refresh_presision == refresh_presision):
				raise InvalidMeasurementError("There are diferents values for the same measurement.")
		return m