(self, word)
update vocab statis
update vocab statis
update vocab statis
def add(self, word):
    ''' update vocab statis'''
    if word not in self._mapping:
      self._mapping[word] = len(self._mapping)
    self._freq[word] += 1
def add ( self , word ) : if word not in self . _mapping : self . _mapping [ word ] = len ( self . _mapping ) self . _freq [ word ] += 1