def _string_value(client, value):
    """Converts a value to a protocol buffer string wrapper.

    Args:
      client: A google.ads.google_ads.client.GoogleAdsClient instance.
      value: A string value to wrap.

    Returns:
      The value wrapped in a google.ads.googleads_v2.types.StringValue.
    """
    string_val = client.get_type('StringValue', version='v3')
    string_val.value = value
    return string_val