parameters: (self, key, value)
docstring: Raise error, if one tries to edit the VocabEntry.
docstring_summary: Raise error, if one tries to edit the VocabEntry.
docstring_tokens: Raise error if one tries to edit the VocabEntry .
function: def __setitem__(self, key, value):
          """ Raise error, if one tries to edit the VocabEntry.
          """
          raise ValueError('vocabulary is readonly')
function_tokens: def __setitem__ ( self , key , value ) : raise ValueError ( 'vocabulary is readonly' )