Calculate mean and stdev for most recent 1000 block times

poisson.py

from bitcoinrpc.authproxy import AuthServiceProxy, JSONRPCException
from datetime import datetime
from dateutil import tz
import numpy

N = 1000
rpc_connection = AuthServiceProxy("http://[name]:[pass]@127.0.0.1:8332")
best_block_hash = rpc_connection.getbestblockhash()
tip = rpc_connection.getblock(best_block_hash)
max = tip["height"]
commands = [ [ "getblockhash", height] for height in range(max-N, max) ]
block_hashes = rpc_connection.batch_(commands)
blocks = rpc_connection.batch_([ [ "getblock", h ] for h in block_hashes ])
block_times = [ block["time"] for block in blocks ]
times = numpy.diff(block_times)
print("block times avg={:.2f} std={:.2f}".format(numpy.mean(times), numpy.std(times)))