You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: symbol.rb
    path of file: ./repos/picky/server/lib/picky/extensions
    
    the code of the file until where you have to start completion: # Extending the Symbol class.
#
class Symbol

  # Returns a _single_ dou
    
  def each_subtoken from_length = 1, range = nil
    sub = self.id2name

    if range
      unless (range.first.zero? && range.last == -1)
        sub = sub[range]
      end