When generating API stubs with the scaffold utility using, e.g., `python -m localstack.aws.scaffold sns`,
the scaffold creates method names from operation names, which are ugly when acronyms (subsequent uppercase characters that belong together).

Example:
`CreateSMSSandboxPhoneNumber` -> `create_s_m_s_sandbox_phone_number`

it would be nicer to have `create_sms_sandbox_phone_number`

This is a limitation of this method: https://github.com/localstack/localstack/blob/1888e66b85d7e6a8ee457bc7a732984fcf7aa830/localstack/utils/common.py#L978-L979
fn = common.format_number
        self.assertEqual("12", fn(12, decimals=0))
        self.assertEqual("12", fn(12, decimals=1))
        self.assertEqual("12", fn(12.421, decimals=0))
        self.assertEqual("13", fn(12.521, decimals=0))
        self.assertEqual("12.52", fn(12.521, decimals=2))
        self.assertEqual("12.521", fn(12.521, decimals=3))
        self.assertEqual("12.521", fn(12.521, decimals=4))
        self.assertEqual("-12.521", fn(-12.521, decimals=4))
        self.assertEqual("-1223.4354", fn(-1.2234354123e3, decimals=4))
    def test_cleanup_threads_and_processes_calls_shutdown_hooks(self):