Abstract Implementation of Euler number using a function

import math
def e(n):
    # for type safety, and as we are exacting decimal cast the return value
    return float(1 + sum([1/math.factorial(a) for a in range(n) if a != 0]))

x = 20
# cut it off at 15 decimal places
# append f to :.precision to round it up
print("euler to 300 decimal places{:.20f}".format(e(x)))
print("euler to 15 decimal places{:.15}".format(math.e))
print("euler to 10 decimal places{:.10}".format(e(x)) , "{:.15}".format(math.e))
# module above uses a convergering sequence to converge at euler number.