class_docstr: A 2-line progress bar.
  
  The progress bar looks roughly like this in the console::
  
                              Header
      20% [===========----------------------------------]
  
  The progress bar is colored, if the terminal supports color
  output; and adjusts to the width of the terminal.
class_docstr_tok: ["A","2-line","progress","bar",".","The","progress","bar","looks","roughly","like","this","in","the","console",":",":","Header","20","%","[","===========","--","--","--","--","--","--","--","--","--","--","--","--","--","--","--","--","--","]","The","progress","bar","is","colored",",","if","the","terminal","supports","color","output",";","and","adjusts","to","the","width","of","the","terminal","."]
docstr: Updates the progress bar.
  
  @param percent: the percentage to be shown. If C{None}, the previous
    value will be used.
  @param message: the message to be shown above the progress bar. If
    C{None}, the previous message will be used.
code: def update(self, percent=None, message=None):
      """Updates the progress bar.
  
      @param percent: the percentage to be shown. If C{None}, the previous
        value will be used.
      @param message: the message to be shown above the progress bar. If
        C{None}, the previous message will be used.
      """
      if self.cleared:
          sys.stdout.write("\n" + self.header)
          self.cleared = False
  
      if message is None:
          message = self.last_message
      else:
          self.last_message = message
  
      if percent is None:
          percent = self.last_percent
      else:
          self.last_percent = percent
  
      n = int((self.width - 10) * (percent / 100.0))
      sys.stdout.write(
          self.term.BOL
          + self.term.UP
          + self.term.UP
          + self.term.CLEAR_EOL
          + self.term.render(self.HEADER % message.center(self.width))
          + (
              self.progress_bar
              % (percent, "=" * n, "-" * (self.width - 10 - n))
          )
          + "\n"
      )
  
imports: from abc import ABCMeta, abstractmethod
  import re
  import sys
  from igraph import __version__
  from igraph._igraph import set_progress_handler, set_status_handler
  from igraph.configuration import Configuration
label_desc: Use image node_id 2 for calling the ProgressBar obj's underlying member method code with example usage: obj.update(percent, message) without return types