docs: def add_criterion(self, criterion):
          """
          Adds Decision Criteria to the probnet dict.
  
          Parameters
          ----------
          criterion: <Element Criterion at Decision Criteria Node in XML>
              etree Element consisting DecisionCritera tag.
  
          Examples
          -------
          >>> reader = ProbModelXMLReader()
          >>> reader.add_criterion(criterion)
          """
          criterion_name = criterion.attrib['name']
          self.probnet['DecisionCriteria'][criterion_name] = {}
          if criterion.find('AdditionalProperties/Property') is not None:
              for prop in criterion.findall('AdditionalProperties/Property'):
                  prop_name = prop.attrib['name']
                  prop_value = prop.attrib['value']
                  self.probnet['DecisionCriteria'][criterion_name]['AdditionalProperties'][prop_name] = prop_value