from functools import partial

def func(a, b, c=0):
    return a - b - c

p1 = partial(func, 1)

print(p1(2))    # -1
%timeit p1(2)   # 100 ns

p1.keywords['c'] = 1
print(p1(2))    # -2
%timeit p1(2)   # 234 ns

del p1.keywords['c']
print(p1(2))    # -1
%timeit p1(2)   # 144 ns

p1 = partial(func, 1)

print(p1(2))    # -1
%timeit p1(2)   # 100 ns

p1.keywords['c'] = 1
print(p1(2))    # -2
%timeit p1(2)   # 234 ns

del p1.keywords['c']
print(p1(2))    # -1
%timeit p1(2)   # 100 ns