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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_to_dict(fields):
 """ Build dictionnary which dependancy for each field related to "root" fields = ["toto", "toto__tata", "titi__tutu"] dico = { "toto": { EMPTY_DICT, "tata": EMPTY_DICT }, "titi" : { "tutu": EMPTY_DICT } } EMPTY_DICT is useful because we don't lose field without it dico["toto"] would only contains "tata" inspired from django.db.models.sql.add_select_related """

    field_dict = {}
    for field in fields:
        d_tmp = field_dict
        for part in field.split(LOOKUP_SEP)[:-1]:
            d_tmp = d_tmp.setdefault(part, {})
        d_tmp = d_tmp.setdefault(
            field.split(LOOKUP_SEP)[-1],
            deepcopy(EMPTY_DICT)
        ).update(deepcopy(EMPTY_DICT))
    return field_dict