code: def token_clean(self, length, numbers=True):
  
          
  
          def clean1(tokens):
              return [t for t in tokens if t.isalpha() == 1 and len(t) > length]
  
          def clean2(tokens):
              return [t for t in tokens if t.isalnum() == 1 and len(t) > length]
  
          if numbers:
              self.tokens = list(map(clean1, self.tokens))
          else:
              self.tokens = list(map(clean2, self.tokens))
docs: Strip out non-alphanumeric tokens.
          length: remove tokens of length "length" or less.
          numbers: strip out non-alpha tokens.