Для проверки использования электронной почты используйте email_validator
from email_validator import validate_email, EmailNotValidError
def check_email(email):
try:
v = validate_email(email) # validate and get info
email = v["email"] # replace with normalized form
print("True")
except EmailNotValidError as e:
# email is not valid, exception message is human-readable
print(str(e))
check_email("test@gmailcom")