Fig.3 QElectroTech Toolbar:
The Fig.3 shows the next segment of the tool bar containing active buttons. The options provided here are Add a textfield, Add a picture, Add a mechanical connection (straight line tool), Add a rectangular area, Add an ellipse area and Add a polyline area. The options from Add a mechanical connection are primarily special drawing aids in the main window. These are selected by single left mouse click and deselected by pressing the Esc key from the keyboard. The operation of these geometry buttons are enumerated here:

Fig.2 QElectroTech Toolbar:
The Fig.2 shows the first segment of the tool bar containing some active buttons and some inactive buttons. The options provided here apply to the entire but, to the selected project only. Clicking New will create a new project in the same window, similarly other active options are Save or Save as changes, Close the project, Print the project etc.,. The inactive buttons shown here work on individual element or selected elements that is / are added to the drawing. These options are activated when elements are selected. Individual element can be selected with a single left mouse click. Multiple elements can be selected by holding the control key from keyboard and selecting each element with a left mouse click. The tool bar buttons perform the action on all the selected elements simultaneously. The buttons provided here are Undo, Redo, Cut, Copy, Paste, Delete, Rotate and Properties.

Fig.4 QElectroTech Toolbar:
The Fig.4 shows the next segment of the tool bar containing three active buttons. The options provided here are Diagram properties, Reset conductors, and Automatic conductor creation.

Why must 'self' be used explicitly in method definitions and calls?

Sequence Types --- str, unicode, list, tuple, bytearray, buffer, xrange