@staticmethod<EOL><INDENT>def serialize_asset_key_with_slash(asset_key):<DEDENT>
url = unicode(asset_key)<EOL>if not url.startswith('<STR_LIT:/>'):<EOL><INDENT>url = '<STR_LIT:/>' + url<EOL><DEDENT>return url<EOL>
Legacy code expects the serialized asset key to start w/ a slash; so, do that in one place

Args:
    asset_key (str): Asset key to generate URL