ros2 concatenate LaunchConfiguration with string for function argument

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In a ros2 python launch script, I want to concatenate a LaunchConfiguration with a string and pass it to a function. I can't seem to figure out how to do this.

def load_file(package_name, file)
   # body of function

prefix = LaunchConfiguration("name")

# package_name = prefix + "_pkg"
contents = load_file(package_name, file)

Here package_name needs to be the concatenation of a LaunchConfiguration and a literal string. There must be a way I can do this - no?