How do I get the default fill values?

How can I get the default fill values using netcdf4-python? According to this issue one can get it via netCDF4._default_fillvals, but this gives AttributeError: module 'netCDF4' has no attribute '_default_fillvals' 1.5.0.1. The information is available somewhere, because print(v) tells me filling on, default _FillValue of 9.969209968386869e+36 used. Unfortunately the file has not set the fill value attribute. Short of parsing the output of v.__repr__(), how can I find the default fill value?

This is documented in a parenthetical remark in the documentation for Dataset.create_variable

From the Changelog for version 0.9.7:

* changed netCDF4._default_fillvals to netCDF4.default_fillvals (to make part of public API). Added to docs (issue 94).

From the documentation for the Dataset.create_variable static method:

The optional keyword fill_value can be used to override the default netCDF _FillValue (the value that the variable gets filled with before any data is written to it, defaults given in netCDF4.default_fillvals). If fill_value is set to False, then the variable is not pre-filled.

This was fixed in commit 36f6544b10f791f31c3a0911ea97351e03490c75.