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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 field_cols(model):
 """ Get the models columns in a friendly SQL format This will be a string of comma separated field names prefixed by the models resource type. TIP: to_manys are not located on the table in Postgres & are instead application references, so any reference to there column names should be pruned! :return: str """


        to_many = model.to_many
        cols = [f for f in model.all_fields if f not in to_many]
        cols = ', '.join(cols)

        return cols or None