code: def get_datatype_str(self, element, length):
          '''get_datatype_str
  
          High-level api: Produce a string that indicates the data type of a node.
  
          Parameters
          ----------
  
          element : `Element`
              A node in model tree.
  
          length : `int`
              String length that has been consumed.
  
          Returns
          -------
  
          str
              A string that indicates the data type of a node.
          '''
  
          spaces = ' '*(self.get_width(element) - length)
          type_info = element.get('type')
          ret = ''
          if type_info == 'anyxml' or type_info == 'anydata':
              ret = spaces + '<{}>'.format(type_info)
          elif element.get('datatype') is not None:
              ret = spaces + element.get('datatype')
          if element.get('if-feature') is not None:
              return ret + ' {' + element.get('if-feature') + '}?'
          else:
              return ref get_datatype_str(self, element, length):
          '''get_datatype_str
  
          High-level api: Produce a string that indicates the data type of a node.
  
          Parameters
          ----------
  
          element : `Element`
              A node in model tree.
  
          length : `int`
              String length that has been consumed.
  
          Returns
          -------
  
          str
              A string that indicates the data type of a node.
          '''
  
          spaces = ' '*(self.get_width(element) - length)
          type_info = element.get('type')
          ret = ''
          if type_info == 'anyxml' or type_info == 'anydata':
              ret = spaces + '<{}>'.format(type_info)
          elif element.get('datatype') is not None:
              ret = spaces + element.get('datatype')
          if element.get('if-feature') is not None:
              return ret + ' {' + element.get('if-feature') + '}?'
          else:
              return ret
docs: get_datatype_str
  
          High-level api: Produce a string that indicates the data type of a node.
  
          Parameters
          ----------
  
          element : `Element`
              A node in model tree.
  
          length : `int`
              String length that has been consumed.
  
          Returns
          -------
  
          str
              A string that indicates the data type of a node.