NameError: name 'TICKER' is not defined

[massb]

I keep getting this error:

NameError: name 'TICKER' is not defined

When I run:

from cryptofeed import FeedHandler

fh = FeedHandler()

# ticker, trade, and book are user defined functions that
# will be called when ticker, trade and book updates are received
ticker_cb = {TICKER: TickerCallback(ticker)}
trade_cb = {TRADES: TradeCallback(trade)}
gemini_cb = {TRADES: TradeCallback(trade), L2_BOOK: BookCallback(book)}

fh.add_feed(Coinbase(pairs=['BTC-USD'], channels=[TICKER], callbacks=ticker_cb))
fh.add_feed(Bitfinex(pairs=['BTC-USD'], channels=[TICKER], callbacks=ticker_cb))
fh.add_feed(Poloniex(pairs=['BTC-USDT'], channels=[TRADES], callbacks=trade_cb))
fh.add_feed(Gemini(pairs=['BTC-USD', 'ETH-USD'], channels=[TRADES, L2_BOOK], callbacks=gemini_cb))

fh.run()

[lagerfeuer]

This is the wrong repository, you're looking for cryptofeed.