boltons should be builtins. Boltons is a set of over 160 BSD-licensed, pure-Python utilities in the same spirit as--and yet conspicuously missing from--the standard library.
conda install -c conda-forge boltons
conda install -c "conda-forge/label/cf201901" boltons
conda install -c "conda-forge/label/cf202003" boltons
conda install -c "conda-forge/label/gcc7" boltons