Uncaught TypeError: can't convert BigInt to number when computing means

[ghpu]

"arquero": "6.0.1"

I found that there is an integrated pull request adding BigInt support for sum, median, quantile, etc. (https://github.com/uwdata/arquero/pull/26) but not for mean operator.

[ghpu]

I got the problem because my data came from a parquet file with a BigInt column.