docs: def read_file(self, infile):
          """Read a reST file into a string.
          """
          try:
              with open(infile, 'rt') as file:
                  return file.read()
          except UnicodeDecodeError as e:
              err_exit('Error reading %s: %s' % (infile, e))
          except (IOError, OSError) as e:
              err_exit('Error reading %s: %s' % (infile, e.strerror or e))