[Discuss-gnuradio] a simple question from a beginner

[Murtuza]

Hi frnds

I am new to GNURadio and I have a simple question the answer to which I cannot find. I tried all kinds of methods to know what's happening. This is my last way to know the answer. I am looking at tunnel.py in gnuradio/examples/digital directory. In this module in the main() function we initialize the variable "mods" as

mods = modulation_utils.type_1_mods()

The modulation_utils.type_1_mods() returns the variable _type_1_modulators. This variable is actually initialized as an empty dictionary object {}, but when it returns to tunnel.py it returns a dictionary  modulators info. I cannot find where this initialization is being done. I checked almost everything, all the import modules, etc. I tried debugging using pdb and a lot of print statements, but still can't find the answer to it. Can anyone throw some light on it. 

_type_1_modulators = {}

# something seems to happen between these two lines. I don't know what. 

def type_1_mods():
    print "inside function"
    print _type_1_modulators
    return _type_1_modulators    

Thanking you
Ali