'Determine the function that computes a cache key from arguments.'

def determine_key(self):

    assert (self.skiparg is None), 'ormcache_multi()    no    longer    supports    skiparg'
    assert isinstance(self.multi, basestring), 'ormcache_multi()    parameter    multi    must    be    an    argument    name'
    super(ormcache_multi, self).determine_key()
    spec = getargspec(self.method)
    args = formatargspec(*spec)[1:(-1)]
    code_multi = ('lambda    %s:    %s' % (args, self.multi))
    self.key_multi = unsafe_eval(code_multi)
    self.multi_pos = spec.args.index(self.multi)
