Custom Exceptions

import sys


if len(sys.argv) > 1:
  reader = open(sys.argv[1])
else:
  reader = sys.stdin


x = float(reader.readline())
y = float(reader.readline())


if y == 0:
  print("Error")
else:
  z = x / y
  print(z)

import sys


if len(sys.argv) > 1:
  reader = open(sys.argv[1])
else:
  reader = sys.stdin


x = float(reader.readline())
y = float(reader.readline())


if y == 0:
  print("Error")
else:
  z = x / y
  print(z)

import sys


if len(sys.argv) > 1:
  reader = open(sys.argv[1])
else:
  reader = sys.stdin


x = float(reader.readline())
y = float(reader.readline())


if y == 0:
  raise ValueError("Cannot divide by zero")
else:
  z = x / y
  print(z)

import sys


if len(sys.argv) > 1:
  reader = open(sys.argv[1])
else:
  reader = sys.stdin


x = float(reader.readline())
y = float(reader.readline())


if y == 0:
  raise ValueError("Cannot divide by zero")
else:
  z = x / y
  print(z)