def _compute_paths_to_names(env):
reduced = copy.deepcopy(env)<EOL>for pathvar in ["<STR_LIT>"]:<EOL><INDENT>_, reduced[pathvar] = os.path.split(reduced[pathvar])<EOL><DEDENT>return reduced<EOL>
Single-environment version of conversion of filepath(s) to name(s).

This is similarly motivated by allowing tests' assertions about
equality between Mappings to be independent of Project instance's
effort to ensure that filepaths are absolute.

:param Mapping env: environment datum by name
:return Mapping: same as the input, but with conversion(s) performed