parameters: (self, value)
docstring: Append a value to the list if it isn't already present.
  
          value is the value to append.
docstring_summary: Append a value to the list if it isn't already present.
docstring_tokens: Append a value to the list if it isn t already present .
function: def append(self, value):
          """Append a value to the list if it isn't already present.
  
          value is the value to append.
          """
          if value not in self._list:
              self._list.append(value)
function_tokens: def append ( self , value ) : if value not in self . _list : self . _list . append ( value )