def RetrieveObject(self, ui, start=-<NUM_LIT:1>, length=-<NUM_LIT:1>):
if self.file and ui:<EOL><INDENT>if length == -<NUM_LIT:1>:<EOL><INDENT>len = ui.length<EOL><DEDENT>else:<EOL><INDENT>len = length<EOL><DEDENT>if start == -<NUM_LIT:1>:<EOL><INDENT>st = <NUM_LIT:0><EOL><DEDENT>else:<EOL><INDENT>st = int(start)<EOL><DEDENT>return chmlib.chm_retrieve_object(self.file, ui, st, len)<EOL><DEDENT>else:<EOL><INDENT>return (<NUM_LIT:0>, '<STR_LIT>')<EOL><DEDENT>
Retrieves the contents of a document.
        This function takes a UnitInfo and two optional arguments, the first
        being the start address and the second is the length. These define
        the amount of data to be read from the archive.