class_docstr: Main class; contains all subelements: book -> page -> block -> par -> line -> format
class_docstr_tok: ["Main","class",";","contains","all","subelements",":","book","-",">","page","-",">","block","-",">","par","-",">","line","-",">","format"]
docstr: Writes all information of the book element and all sub elements into the python console.
  :return: None
docstr_tok: ["Writes","all","information","of","the","book","element","and","all","sub","elements","into","the","python","console",".",":","return",":","None"]
code: def __str__(self):
      """
      Writes all information of the book element and all sub elements into the python console.
      :return: None
      """
  
      s = ""
  
      for page in self.pages:
          s += page
          for block in page.blocks:
              s += "     " + block.__str__()
              for par in block.pars:
                  s += "         " + par.__str__()
                  for line in par.lines:
                      s += "              " + line.__str__()
                      for format in line.formats:
                          s += "                  " + format.__str__()
  
label_desc: Use image node_id 2 for calling the Book obj's underlying member method code with example usage: obj.__str__() without return types