NAME
	function_exists - determine if a function exist in an object or not

SYNTAX
	string function_exists(string str, object ob)

DESCRIPTION
	Return the file name of the program that defines the function str
	in object ob. The returned value can be other than file_name(ob)
	if the function is defined by an inherited object.
	0 is returned if the function was not defined.

SEE ALSO
	get_function