python π.py Σ.py

import math
π = math.pi

def Σ(*args):
    """数式が定義できる"""
    r = 0
    for a in args:
        r += a
    return r

def 円周(半径):
    return 2 *半径 * π

print(円周(3))
#18.84955592153876
print(Σ(5,4,3,2,1))
#15