This is a static method which creates a new GtkExpander instance using label as the text of the label. If characters in label are preceded by an underscore, they are underlined. If you need a literal underscore character in a label, use '__' (two underscores). The first underlined character represents a keyboard accelerator called a mnemonic. Pressing Alt with that key activates the button. If label is Null the expander will have no label.
This method must be called statically.