def __init__(self, parent=None):  # Constructor of the class.
     super(UWindow, self).__init__(parent)  # Initialization of the class.
     self.menubar = UMBar()  # Menu Bar for main window.
     self.mb1 = UMenu(self.menubar)  # First Menu for Menu Bar.
     self.mb1.addAction("Open")  # Menu, that will create,
     self.mb1.addAction("Save")  # open and save files and
     self.mb1.addAction("Print")  # open print dialog with
     self.mb1.addAction("Print Preview")  # open print preview dialog,
     self.mb1.setTitle("&File")  # used in the application.
     self.mb2 = UMenu(self.menubar)  # Second Menu for Menu Bar.
     self.mb2.addAction("Undo")  # Adding of the elements of
     self.mb2.addAction("Redo")  # the Menu that will edit
     self.mb2.addAction("Cut")  # some documents created with
     self.mb2.addAction("Copy")  # this app, undoes and redoes
     self.mb2.addAction("Paste")  # operations, cut/copy/past
     self.mb2_1 = self.mb2.addMenu("&Alignment")
     self.mb2_1.addAction("center")  # for the text edit field.
     self.mb2_1.addAction("left")  # Adding of the submenu for
     self.mb2_1.addAction("right")  # alignment of the text in the
     self.mb2_1.addAction("justify")  # text field by center, right,
     self.mb2.addAction("Text Color")  # left, and justified. Adding
     self.mb2.addAction("Text Font")  # options for change color and
     self.mb2.setTitle("&Edit")  # font for selected text.
     self.mb3 = UMenu(self.menubar)  # Third Menu for Menu Bar.
     self.mb3.addAction("Pickle")  # Add elements to provide
     self.mb3.addAction("Shelve")  # open the data with pickle,
     self.mb3.addAction("CSV")  # shelve, csv, pandas, sqlite,
     self.mb3.addAction("Pandas")  # postgresql, mysql, qtsql
     self.mb3.addAction("SQLite")  # module operations, NoSQL
     self.mb3.addAction("PostgreSQL")  # databases MongoDB, CouchDB.
     self.mb3.addAction("MySQL")  # Each option will open the
     self.mb3.addAction("MongoDB")  # file/db with providing
     self.mb3.addAction("CouchDB")  # functionality dependent on
     self.mb3.setTitle("&Data")  # selected option.
     self.mb4 = UMenu(self.menubar)  # Fourth Menu for Menu Bar.
     self.mb4.addAction("Settings")  # Add elements to provide
     self.mb4.addAction("Run")  # some settings, run and
     self.mb4.addAction("Configuration")  # configure some parameters
     self.mb4.setTitle("&Options")  # of the app as some options.
     self.mb5 = UMenu(self.menubar)  # Fifth Menu for Menu Bar.
     self.mb5.addAction("Online Help")  # Provides links to online
     self.mb5.addAction("Documentation")  # help and other docs that
     self.mb5.setTitle("&Help")  # will related to this app.
     self.menubar.addMenu(self.mb1)  # Add first menu to menu bar.
     self.menubar.addMenu(self.mb2)  # Add second menu to menu bar.
     self.menubar.addMenu(self.mb3)  # Add third menu to menu bar.
     self.menubar.addMenu(self.mb4)  # Add fourth menu to menu bar.
     self.menubar.addMenu(self.mb5)  # Add fifth menu to menu bar.
     self.setMenuBar(self.menubar)  # And set menu bar to window.
     self.tabwid = UTWid()  # Tab Widget for main window.
     self.twid1 = UWid()  # First widget for tab widget.
     self.twid2 = UWid()  # Second widget for tabwidget.
     self.twid3 = UWid()  # Third widget for tab widget.
     self.tabwid.addTab(self.twid1, "Applications")
     self.tabwid.addTab(self.twid2, "Visualization")
     self.tabwid.addTab(self.twid3, "Documents")
     self.setCentralWidget(self.tabwid)  # Central widget as tabwidget.
     self.stat_bar = USBar()  # Create status bar object.
     self.setStatusBar(self.stat_bar)  # Set status bar.
class UWindow(UWin):                           # Create the Main Window.
    
    def __init__(self, parent=None):           # Constructor of the class.
        super(UWindow, self).__init__(parent)  # Initialisation of the class.
        self.menubar = UMBar()                 # Menu Bar for main window.
        self.mb1 = UMenu(self.menubar)         # First Menu for Menu Bar.
        self.mb1.addAction("Open")             # Menu, that will create,
        self.mb1.addAction("Save")             # open and save files and 
        self.mb1.addAction("Print")            # open print dialog with 
        self.mb1.addAction("Print Preview")    # open print preview dialog,
        self.mb1.setTitle("&File")             # used in the application.
        self.mb2 = UMenu(self.menubar)         # Second Menu for Menu Bar.
        self.mb2.addAction("Cut")              # Adding of the elements of
        self.mb2.addAction("Copy")             # the Menu that will edit
        self.mb2.addAction("Paste")            # some documents created with
        self.mb2.setTitle("&Edit")             # this app, and set title.
        self.mb3 = UMenu(self.menubar)         # Third Menu for Menu Bar.
        self.mb3.addAction("Settings")         # Add elements to provide 
        self.mb3.addAction("Run")              # some settings, run and
        self.mb3.addAction("Configuration")    # configure some parameters
        self.mb3.setTitle("&Options")          # of the app as some options.
        self.mb4 = UMenu(self.menubar)         # Fourth Menu for Menu Bar.
        self.mb4.addAction("Online Help")      # Provides links to online
        self.mb4.addAction("Documentation")    # help and other docs that
        self.mb4.setTitle("&Help")             # will related to this app.
        self.menubar.addMenu(self.mb1)         # Add first menu to menu bar.
        self.menubar.addMenu(self.mb2)         # Add second menu to menu bar.
        self.menubar.addMenu(self.mb3)         # Add third menu to menu bar.
        self.menubar.addMenu(self.mb4)         # Add fourth menu to menu bar.
        self.setMenuBar(self.menubar)          # And set menu bar to window.
        self.tabwid = UTWid()                  # Tab Widget for main window.
        self.twid1 = UWid()                    # First widget for tab widget.
        self.twid2 = UWid()                    # Second widget for tabwidget.
        self.twid3 = UWid()                    # Third widget for tab widget.
        self.tabwid.addTab(self.twid1, "Applications")
        self.tabwid.addTab(self.twid2, "Visualization")
        self.tabwid.addTab(self.twid3, "Documents")
        self.setCentralWidget(self.tabwid)     # Central widget as tabwidget.
        self.stat_bar = USBar()                # Create status bar object.
        self.setStatusBar(self.stat_bar)       # Set status bar.