docs: def set_const(const, val):
      '''Convenience wrapper to reliably set the value of a constant from
         outside of package scope'''
      try:
          cur = getattr(_c, const)
      except AttributeError:
          raise FSQEnvError(errno.ENOENT, u'no such constant:'\
                            u' {0}'.format(const))
      except TypeError:
          raise TypeError(errno.EINVAL, u'const name must be a string or'\
                          u' unicode object, not:'\
                          u' {0}'.format(const.__class__.__name__))
      should_be = cur.__class__
      try:
          if not isinstance(val, should_be):
              if should_be is unicode or cur is None:
                  val = coerce_unicode(val, _c.FSQ_CHARSET)
              elif should_be is int and const.endswith('MODE'):
                  val = int(val, 8)
              elif isinstance(cur, numbers.Integral):
                  val = int(val)
              else:
                  should_be(val)
      except (TypeError, ValueError, ):
          raise FSQEnvError(errno.EINVAL, u'invalid type for constant {0},'\
                            u' should be {1}, not:'\
                            u' {2}'.format(const, should_be.__name__,
                                           val.__class__.__name__))
      setattr(_c, const, val)
      return val