import re


def is_valid_email(email):
	"""
	return True if email is a valid email and
	False if email is not a valid email.

	email - (str) an email to be validated
	"""
	regex = '^[a-z0-9]+[\._]?[a-z0-9]+[@]\w+[.]\w{2,3}$'
	if (re.search(regex,email)):
		return True
	else:
		return False