def load(
    obj,
    env=None,
    silent=True,
    key=None,
    filename=None,
    validate=False,
    identifier="yaml",
):
    """
    Reads and loads in to "obj" a single key or all keys from source file.

    :param obj: the settings instance
    :param env: settings current env default='development'
    :param silent: if errors should raise
    :param key: if defined load a single key, else load all in env
    :param filename: Optional custom filename to load
    :return: None
    """
    # Resolve the loaders
    # https://github.com/yaml/pyyaml/wiki/PyYAML-yaml.load(input)-Deprecation
    # Possible values are:
    #   `safe_load, full_load, unsafe_load, load, safe_load_all`
    yaml_reader = getattr(
        yaml, obj.get("YAML_LOADER_FOR_DYNACONF"), yaml.safe_load
    )
    if yaml_reader.__name__ == "unsafe_load":  # pragma: no cover
        warn(
            "yaml.unsafe_load is deprecated."
            " Please read https://msg.pyyaml.org/load for full details."
            " Try to use full_load or safe_load."
        )

    _loader = BaseLoader
    if yaml_reader.__name__.endswith("_all"):
        _loader = AllLoader

    # when load_file function is called directly it comes with module and line number
    if isinstance(identifier, SourceMetadata) and identifier.loader.startswith(
        "load_file"
    ):
        identifier = identifier.loader

    loader = _loader(
        obj=obj,
        env=env,
        identifier=identifier,
        extensions=YAML_EXTENSIONS,
        file_reader=yaml_reader,
        string_reader=yaml_reader,
        validate=validate,
    )
    loader.load(
        filename=filename,
        key=key,
        silent=silent,
    )

    Reads and loads in to "obj" a single key or all keys from source file.

    :param obj: the settings instance
    :param env: settings current env default='development'
    :param silent: if errors should raise
    :param key: if defined load a single key, else load all in env
    :param filename: Optional custom filename to load
    :return: None
    
dynaconf/loaders/yaml_loader.py