':return: The headers we want to use framework-wide for fuzzing. By
default we set the fuzzable_headers to [], which makes this
method return an empty Headers instance.
When the user sets a fuzzable_headers it will create a Headers
instance with empty values.
We then append the specific headers supplied for this
FuzzableRequest instance to the default headers. Any specific
headers override the default (empty) ones.'

def get_default_headers(self):

    fuzzable_headers = (cf.cf.get('fuzzable_headers') or [])
    req_headers = [(h, '') for h in fuzzable_headers]
    return Headers(init_val=req_headers)
