Blender Doesn't Permit Indices in Drivers?

I have a variable in a driver that I would like to be able to “switch on and off”. To do this, I figured I could give this variable a power, another variable that would link to a custom property. I can then make the custom property 1, for enabled, or 0 for disabled - as a number to the power 0 is 1 and 1 multiplied by another number is just that other number.

I.e. x^y*z .

However Blender doesn’t seem to support this. Here is the error from the console:
Traceback (most recent call last):
File “<bpy driver>”, line 1, in <module>
TypeError: unsupported operand type(s) for ^: ‘float’ and ‘float’

Any ideas as to why this is? It seems like pretty standard math to me. If not, any ideas how to get around it?