def __at_om_to_im(self, om):
original_om = om<EOL>if om[<NUM_LIT:0>] == '<STR_LIT>':<EOL><INDENT>om = om[<NUM_LIT:1>:]<EOL>is_um = True<EOL><DEDENT>else:<EOL><INDENT>is_um = False<EOL><DEDENT>if om == '<STR_LIT:r>':<EOL><INDENT>return (original_om, O_RDONLY, False, is_um)<EOL><DEDENT>elif om == '<STR_LIT:w>':<EOL><INDENT>return (original_om, O_WRONLY | O_CREAT | O_TRUNC, False, is_um)<EOL><DEDENT>elif om == '<STR_LIT:a>':<EOL><INDENT>return (original_om, O_WRONLY | O_CREAT, False, is_um)<EOL><DEDENT>elif om == '<STR_LIT>':<EOL><INDENT>return (original_om, O_RDWR | O_CREAT, False, is_um)<EOL><DEDENT>elif om == '<STR_LIT>':<EOL><INDENT>return (original_om, O_RDWR | O_CREAT | O_TRUNC, False, is_um)<EOL><DEDENT>elif om == '<STR_LIT>':<EOL><INDENT>return (original_om, O_RDWR | O_CREAT, True, is_um)<EOL><DEDENT>else:<EOL><INDENT>raise Exception("<STR_LIT>" % <EOL>(original_om))<EOL><DEDENT>
Convert an "outer" access mode to an "inner" access mode.
        Returns a tuple of:

            (<system access mode>, <is append>, <is universal newlines>).