def _get_idstr(pyobj):
x = id(pyobj)<EOL>if x < <NUM_LIT:0>:<EOL><INDENT>return '<STR_LIT>' % abs(x)<EOL><DEDENT>return '<STR_LIT>' % x<EOL>
Python 2.3.x generates a FutureWarning for negative IDs, so
    we use a different prefix character to ensure uniqueness, and
    call abs() to avoid the warning.