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
mode = "a" if append else "w+"
    if not isinstance(content, six.string_types):
        mode = mode + "b"
    def _opener(path, flags):
        return os.open(path, flags, permissions)
    
    mkdir(os.path.dirname(file))
    
    with open(file, mode, opener=_opener if permissions else None) as f:
        f.write(content)
        f.flush()
def load_file(file_path, default=None, mode=None):
    if not os.path.isfile(file_path):
        return default
    if not mode:
        mode = "r"
    with open(file_path, mode) as f:
        result = f.read()
    return result
def get_or_create_file(file_path, content=None, permissions=None):