code: def _generate_bq_schema(df, default_type="STRING"):
      
      from pandas_gbq import schema
  
      return schema.generate_bq_schema(df, default_type=default_type)
docs: DEPRECATED: Given a dataframe, generate a Google BigQuery schema.
  
      This is a private method, but was used in external code to work around
      issues in the default schema generation. Now that individual columns can
      be overridden: https://github.com/pydata/pandas-gbq/issues/218, this
      method can be removed after there is time to migrate away from this
      method.