docs: def validate_SUMTO(in_value, restriction):
      """
          Test to ensure the values of a list sum to a specified value:
          Parameters: a list of numeric values and a target to which the values
          in the list must sum
      """
      #Sometimes restriction values can accidentally be put in the template <item>100</items>,
      #Making them a list, not a number. Rather than blowing up, just get value 1 from the list.
      if type(restriction) is list:
          restriction = restriction[0]
  
      value = _get_val(in_value, full=True)
  
      if len(value) == 0:
          return
  
      flat_list = _flatten_value(value)
  
      try:
          sum(flat_list)
      except:
          raise ValidationError("List cannot be summed: %s"%(flat_list,))
  
      if sum(flat_list) != restriction:
          raise ValidationError("SUMTO: %s"%(restriction))