from sqlalchemy.exc import IntegrityError
ins = insert(users).values(
    username="cookiemon",            #This username is already in db,
    email_address="damon@cookie.com", should throw an IntegrityError
    phone="111-111-1111",             for violating unique constraint
    password="password"
    )
try:
    result=connection.execute(ins)
except IntegrityError as error:
    print(error.orig.message, error.params)