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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 _set_id_field(new_class):
 """Lookup the id field for this entity and assign"""

        # FIXME What does it mean when there are no declared fields?
        #   Does it translate to an abstract entity?
        if new_class.meta_.declared_fields:
            try:
                new_class.meta_.id_field = next(
                    field for _, field in new_class.meta_.declared_fields.items()
                    if field.identifier)
            except StopIteration:
                # If no id field is declared then create one
                new_class._create_id_field()