w $zf(-100,"a='./DC hello'") Fetch return value of method in variable "a" from Python

In below command a is storing our return value from Python Script, hello is our device, our python script is returning device type against passing a parameter, this parameter is a device :

w $zf(-100,"a='./DC hello'")

Please help us to fetch return value of method in variable "a" returning from Python in cache.

Thanks in advance, experts