docs: def django_field_to_index(field, **attr):
      '''
      Returns the index field type that would likely be associated with each Django type.
      '''
  
      dj_type = field.get_internal_type()
  
      if dj_type in ('DateField', 'DateTimeField'):
          return DateField(**attr)
      elif dj_type in ('BooleanField', 'NullBooleanField'):
          return BooleanField(**attr)
      elif dj_type in ('DecimalField', 'FloatField'):
          return NumberField(coretype='float', **attr)
      elif dj_type in ('PositiveSmallIntegerField', 'SmallIntegerField'):
          return NumberField(coretype='short', **attr)
      elif dj_type in ('IntegerField', 'PositiveIntegerField', 'AutoField'):
          return NumberField(coretype='integer', **attr)
      elif dj_type in ('BigIntegerField'):
          return NumberField(coretype='long', **attr)
  
      return StringField(**attr)