code: def get_position(directory, identifier):
      
      paragraph_number = get_paragraph_number(identifier)
      paragraph_total = max(  # Not all paragraphs are stored, e.g. because of processing errors.
          get_paragraph_number(get_identifier(document)) + 1
          for document in directory.iterdir())
      assert paragraph_total > paragraph_number and paragraph_total > 0
      position = paragraph_number / paragraph_total
      return position
docs: Extracts the position of a paragraph from the identifier, and the parent directory of the
      paragraph.
  
      Parameters
      ----------
      directory : Path
          A parent directory of a paragraph.
      identifier : str
          An identifier of a paragraph.
  
      Returns
      -------
      float
          The estimated position of the paragraph in the range [0; 1).