I need some advice as to how i access the subfolder of a folder. This is my code so far but i seem to be stuck.

I have a folder called eSessions and under which i have created another folder (say xyz) which i am passing as a parameter to this python script. My aim is to access that subfolder and add a property as shown below but i am confused how to access this xyz subfolder ??? The fname varialbe is passed with xyz in it as an argument.

container.fname.addProperty('memberid',1,int) (this line gives me a problem)
print propertyItems
return printed