A command in a String ?

[Peter Moscatt]

I have a rather odd question:

Is there a way Python can execute a command within a string ?

For example if I had something like:
_str = "fm=OptionMenu(root,xx,'string1','string2','string3')"

And the execute _str.

The reason why I am trying to do this that as I am aware the OptionMenu
hasn't the ability insert options therefore the options would be inserted
by manipulating strings.

Pete