code: def update(self, progress=0):
          
          self.progress += (progress or 1)
          if self.visible:
              if self.progress % self._mod == 1 or\
                 self.progress == self.size - 1:
                  print(self.format_bar(), end="\r")
              if self.progress == (self.size):
                  self.finish()
docs: Updates the progress bar with @progress if given, otherwise
              increments :prop:progress by 1. Also prints the progress bar.
  
              @progress: #int to assign to :prop:progress