Retrieves a sequence of characters. The characters that are retrieved
are those characters at positions from start_pos up to, but not
including end_pos. If end_pos is negative, then the characters
retrieved are those characters from start_pos to the end of the text.
Note that positions are specified in characters, not bytes.
Retrieves a sequence of characters. The characters that are retrieved are those characters at positions from start_pos up to, but not including end_pos. If end_pos is negative, then the characters retrieved are those characters from start_pos to the end of the text. Note that positions are specified in characters, not bytes.