Return the contents of the widget from index1 up to but not including index2 (or just the segment at index1 if index2 is omitted), including text and information about marks, tags, images and windows. The result is a list of (key, value, index) triples, where key is one of 'text', 'mark', 'tagon', 'tagoff', 'image' or 'window'. By default all kinds are reported; passing any of the keyword arguments all, text, mark, tag, image or window as true restricts the dump to the selected kinds. If command is given, it is called once per triple with the three values as arguments and nothing is returned.