extractPArg (PTacImplicit {pname=n, getScript=p1, getTm=p2})
                                      = n : (concatMap extract [p1, p2])
extractPArg (PTacImplicit {pname=n, getScript=p1, getTm=p2})
                                      = n : (concatMap extract [p1, p2])
extractPArg (PTacImplicit {pname=n, getScript=p1, getTm=p2})
                                      = n : (concatMap extract [p1, p2])