'Returns a tuple of cooked fields
:param dj_fields: a list of django name fields
:return:'

def _cooked_fields(self, dj_fields):

    from django.db import models
    valids = []
    for field in dj_fields:
        try:
            (dj_field, _, _, _) = self.model._meta.get_field_by_name(field)
            if isinstance(dj_field, models.ForeignKey):
                valids.append(((field + '_id'), field, dj_field))
            else:
                valids.append((field, field, dj_field))
        except models.FieldDoesNotExist:
            valids.append((field, field, None))
    return valids
