Convert any number of `DidlObjects <DidlObject>` to a unicode xml
    string.

    Args:
        *args (DidlObject): One or more `DidlObject` (or subclass) instances.

    Returns:
        str: A unicode string representation of DIDL-Lite XML in the form
        ``'<DIDL-Lite ...>...</DIDL-Lite>'``.

def to_didl_string(*args):
    """Convert any number of `DidlObjects <DidlObject>` to a unicode xml
    string.

    Args:
        *args (DidlObject): One or more `DidlObject` (or subclass) instances.

    Returns:
        str: A unicode string representation of DIDL-Lite XML in the form
        ``'<DIDL-Lite ...>...</DIDL-Lite>'``.
    """
    didl = XML.Element(
        'DIDL-Lite',
        {
            'xmlns': "urn:schemas-upnp-org:metadata-1-0/DIDL-Lite/",
            'xmlns:dc': "http://purl.org/dc/elements/1.1/",
            'xmlns:upnp': "urn:schemas-upnp-org:metadata-1-0/upnp/",
            'xmlns:r': "urn:schemas-rinconnetworks-com:metadata-1-0/"
        })
    for arg in args:
        didl.append(arg.to_element())
    if sys.version_info[0] == 2:
        return XML.tostring(didl)
    else:
        return XML.tostring(didl, encoding='unicode')