from ccxt how can I get amount of coins I have?

import ccxt
import sys

print('python', sys.version)
print('CCXT Version:', ccxt.__version__)

exchange = ccxt.binance({
    'apiKey': '...',
    'secret': '...',
})
# exchange.verbose = True

print(len([coin for coin, balance in exchange.fetch_balance()
       ['total'].items() if balance > 0]))