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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 get_srid(queryset):
 """Returns the GeoQuerySet spatial reference identifier."""

    try:
        srid = list(six.viewvalues(queryset.query.annotations))[0].srid
    except (AttributeError, IndexError):
        srid = None
    return srid or geo_field(queryset).srid