Backport patch 2.206:

Backport patch 2.206:

    ----------------------------
    revision 2.206
    date: 2003/02/11 16:25:43;  author: gvanrossum;  state: Exp;  lines: +9 -0
    Add basic arg sanity checking to wrap_descr_get().  This is called
    when Python code calls a descriptor's __get__ method.  It should
    translate None to NULL in both argument positions, and insist that at
    least one of the argument positions is not NULL after this
    transformation.
    ----------------------------

which fixes SF bug # 736892, forcing function to act like an unbound
method dumps core.