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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 _split_field_list(field_list):
 """Split the list of fields for which to extract values into lists by extraction methods. - Remove any duplicated field names. - Raises ValueError with list of any invalid field names in ``field_list``. """

    lookup_dict = {}
    generate_dict = {}

    for field_name in field_list or FIELD_NAME_TO_EXTRACT_DICT.keys():
        try:
            extract_dict = FIELD_NAME_TO_EXTRACT_DICT[field_name]
        except KeyError:
            assert_invalid_field_list(field_list)
        else:
            if "lookup_str" in extract_dict:
                lookup_dict[field_name] = extract_dict
            else:
                generate_dict[field_name] = extract_dict

    return lookup_dict, generate_dict