docs: def coerce_single_instance(lookup_field, value):
      """
      Convert from whatever value is given to a scalar value for lookup_field.
      If value is a dict, then lookup_field.name is used to get the value from the dict. Example:
          lookup_field.name = 'id'
          value = {'id': 123, 'name': 'tim'}
          returns = 123
      If value is a model, then lookup_field.name is extracted from the model. Example:
          lookup_field.name = 'id'
          value = <User id=123 name='tim'>
          returns = 123
      Otherwise the value is returned as-is.
  
      :param lookup_field: Peewee model field used for getting name from value.
      :param value: Some kind of value (usually a dict, Model instance, or scalar).
      """
      if isinstance(value, dict):
          return value.get(lookup_field.name)
      if isinstance(value, peewee.Model):
          return getattr(value, lookup_field.name)
      return value