def compile_file(filename, compiler_class=Compiler, **kwargs):
    """Compile a single file (provided as a :class:`pathlib.Path`), and return
    a string of CSS.

    Keyword arguments are passed along to the underlying `Compiler`.

    Note that the search path is set to the file's containing directory by
    default, unless you explicitly pass a ``search_path`` kwarg.

    :param filename: Path to the file to compile.
    :type filename: str, bytes, or :class:`pathlib.Path`
    """
    filename = Path(filename)
    if 'search_path' not in kwargs:
        kwargs['search_path'] = [filename.parent.resolve()]

    compiler = compiler_class(**kwargs)
    return compiler.compile(filename)
Compile a single file (provided as a :class:`pathlib.Path`), and return
    a string of CSS.

    Keyword arguments are passed along to the underlying `Compiler`.

    Note that the search path is set to the file's containing directory by
    default, unless you explicitly pass a ``search_path`` kwarg.

    :param filename: Path to the file to compile.
    :type filename: str, bytes, or :class:`pathlib.Path`