Rename, nulls to nans

[peterdudfield]

Detailed Description

Currently the nans error message and function is called null

Context

• code here
• logging messages here and here
• built on Env vars for nan threshold values #284

Possible Implementation

• rename and update to say nans (not nulls)

[peterdudfield]

Good to check with @devsjc if this is needed

[ram-from-tvl]

Hi @peterdudfield,
Can I take up this issue? I’ll also try to address #284 alongside it. Happy to contribute!
Thanks!