def deepSSE(symbols=None, channels=None, on_data=None, token='<STR_LIT>', version='<STR_LIT>'):
symbols = _strCommaSeparatedString(symbols)<EOL>channels = channels or []<EOL>if isinstance(channels, str):<EOL><INDENT>if channels not in DeepChannelsSSE.options():<EOL><INDENT>raise PyEXception('<STR_LIT>', type(channels))<EOL><DEDENT>channels = [channels]<EOL><DEDENT>elif isinstance(channels, DeepChannelsSSE):<EOL><INDENT>channels = [channels.value]<EOL><DEDENT>elif isinstance(channels, list):<EOL><INDENT>for i, c in enumerate(channels):<EOL><INDENT>if isinstance(c, DeepChannelsSSE):<EOL><INDENT>channels[i] = c.value<EOL><DEDENT>elif not isinstance(c, str) or isinstance(c, str) and c not in DeepChannelsSSE.options():<EOL><INDENT>raise PyEXception('<STR_LIT>', c)<EOL><DEDENT><DEDENT><DEDENT>channels = _strCommaSeparatedString(channels)<EOL>return _streamSSE(_SSE_DEEP_URL_PREFIX.format(symbols=symbols, channels=channels, token=token, version=version), on_data)<EOL>
DEEP is used to receive real-time depth of book quotations direct from IEX.
    The depth of book quotations received via DEEP provide an aggregated size of resting displayed orders at a price and side,
    and do not indicate the size or number of individual orders at any price level.
    Non-displayed orders and non-displayed portions of reserve orders are not represented in DEEP.

    DEEP also provides last trade price and size information. Trades resulting from either displayed or non-displayed orders matching on IEX will be reported. Routed executions will not be reported.

    https://iexcloud.io/docs/api/#deep

    Args:
        symbols (string); Tickers to request
        on_data (function): Callback on data
        token (string); Access token
        version (string); API version