Get the schema field of a model field

    :param Schema schema: a marshmallow schema
    :param str field: the name of the model field
    :return str: the name of the field in the schema

def get_schema_field(schema, field):
    """Get the schema field of a model field

    :param Schema schema: a marshmallow schema
    :param str field: the name of the model field
    :return str: the name of the field in the schema
    """
    schema_fields_to_model = {key: get_model_field(schema, key) for (key, value) in schema._declared_fields.items()}
    for key, value in schema_fields_to_model.items():
        if value == field:
            return key

    raise Exception("Couldn't find schema field from {}".format(field))