class_docstr: Extends QProgressDialog:
  
    * Adds context management so the dialog may be used in `with` statements
    * Allows nesting multiple progress dialogs
  
  Example::
  
      with ProgressDialog("Processing..", minVal, maxVal) as dlg:
          # do stuff
          dlg.setValue(i)   ## could also use dlg += 1
          if dlg.wasCanceled():
              raise Exception("Processing canceled by user")
code: def maximum(self):
      if self.disabled:
          return 0
      return QtWidgets.QProgressDialog.maximum(self)
  
imports: from time import perf_counter
  from ..Qt import QtCore, QtGui, QtWidgets
label_desc: Use image node_id 15 for calling the ProgressDialog obj's underlying member method code with example usage: obj.maximum() and returns: QtWidgets, int