code: def argval(key, default=util_const.NoParam, argv=None):
      
      if argv is None:  # nocover
          argv = sys.argv
  
      keys = [key] if isinstance(key, six.string_types) else key
      n_max = len(argv) - 1
      for argx, item in enumerate(argv):
          for key_ in keys:
              if item == key_:
                  if argx < n_max:
                      value = argv[argx + 1]
                      return value
              elif item.startswith(key_ + '='):
                  value = '='.join(item.split('=')[1:])
                  return value
      value = default
      return value
docs: Get the value of a keyword argument specified on the command line.
  
      Values can be specified as `<key> <value>` or `<key>=<value>`
  
      Args:
          key (str or tuple): string or tuple of strings. Each key should be
              prefixed with two hyphens (i.e. `--`)
          default (Optional[object]): value to return if not specified
          argv (Optional[list]): overrides `sys.argv` if specified
  
      Returns:
          str: value : the value specified after the key. It they key is
              specified multiple times, then the first value is returned.
  
      TODO:
          - [ ] Can we handle the case where the value is a list of long paths?
          - [ ] Should we default the first or last specified instance of the flag.
  
      Example:
          >>> import ubelt as ub
          >>> argv = ['--ans', '42', '--quest=the grail', '--ans=6', '--bad']
          >>> assert ub.argval('--spam', argv=argv) == ub.NoParam
          >>> assert ub.argval('--quest', argv=argv) == 'the grail'
          >>> assert ub.argval('--ans', argv=argv) == '42'
          >>> assert ub.argval('--bad', argv=argv) == ub.NoParam
          >>> assert ub.argval(('--bad', '--bar'), argv=argv) == ub.NoParam
  
      Example:
          >>> # Test fix for GH Issue #41
          >>> import ubelt as ub
          >>> argv = ['--path=/path/with/k=3']
          >>> ub.argval('--path', argv=argv) == '/path/with/k=3'