docs: def sed_inplace(filename, pattern, repl):
      '''
      Perform the pure-Python equivalent of in-place `sed` substitution: e.g.,
      `sed -i -e 's/'${pattern}'/'${repl}' "${filename}"`.
      '''
      # For efficiency, precompile the passed regular expression.
      pattern_compiled = re.compile(pattern)
  
      # For portability, NamedTemporaryFile() defaults to mode "w+b"
      # (i.e., binary writing with updating).
      # This is usually a good thing. In this case, # however, binary writing
      # imposes non-trivial encoding constraints trivially
      # resolved by switching to text writing. Let's do that.
      with tempfile.NamedTemporaryFile(mode='w', delete=False) as tmp_file:
          with open(filename) as src_file:
              for line in src_file:
                  tmp_file.write(pattern_compiled.sub(repl, line))
  
      # Overwrite the original file with the munged temporary file in a
      # manner preserving file attributes (e.g., permissions).
      shutil.copystat(filename, tmp_file.name)
      shutil.move(tmp_file.name, filename)