if not arg.isdigit():
raise ArgError('Argument must be non-negative integer.')
args += [int(arg)]
+ elif tmpl == 'yx_tuple:nonneg':
+ args += [self.parse_yx_tuple(arg, 'nonneg')]
elif tmpl == 'yx_tuple:pos':
args += [self.parse_yx_tuple(arg, 'pos')]
elif tmpl == string_string: