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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 transform_field(field):
 """Customize field appropriately for use in historical model"""

    field.name = field.attname
    if isinstance(field, models.AutoField):
        field.__class__ = models.IntegerField

    elif isinstance(field, models.FileField):
        # Don't copy file, just path.
        field.__class__ = models.TextField

    # Historical instance shouldn't change create/update timestamps
    field.auto_now = False
    field.auto_now_add = False

    if field.primary_key or field.unique:
        # Unique fields can no longer be guaranteed unique,
        # but they should still be indexed for faster lookups.
        field.primary_key = False
        field._unique = False
        field.db_index = True
        field.serialize = True