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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 _normalize_entity(value):
 """Return an entity from an entity or model instance."""

  if ndb is not None and isinstance(value, ndb.Model):
    return None
  if getattr(value, "_populate_internal_entity", None):
    return value._populate_internal_entity()
  return value