def METHOD_NAME(plain: Dict[str, str], sep='.') -> Dict:
    """ Convert plain key/value dictionary into
    a tree by spliting the key with '.'
    Args:
        plain: Dictionary to convert into tree-like structure.
            Keys in this dictionary have to be in a format:
            "[key0].+", e.g: "com.azure.sonic" that
            will be converted into tree like struct:
                {
                    "com": {
                        "azure": {
                            "sonic": {}
                        }
                    }
                }
        sep: Seperator string
    Returns:
        Tree like structure
    """
    res = {}
    for key, value in plain.items():
        if sep not in key:
            res[key] = value
            continue
        namespace, key = key.split(sep, 1)
        res.setdefault(namespace, {})
        utils.deep_update(res[namespace], METHOD_NAME({key: value}))
    return res