LicenseConcluded: LicenseRef-foo/bar

pyspdxtools -i slash.spdx
Traceback (most recent call last):
  File "/opt/homebrew/bin/pyspdxtools", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/click/core.py", line 1157, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/click/core.py", line 1078, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/click/core.py", line 1434, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/click/core.py", line 783, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/spdx_tools/spdx/clitools/pyspdxtools.py", line 61, in main
    document: Document = parse_file(infile)
                         ^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/spdx_tools/spdx/parser/parse_anything.py", line 25, in parse_file
    return tagvalue_parser.parse_from_file(file_name)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/spdx_tools/spdx/parser/tagvalue/tagvalue_parser.py", line 12, in parse_from_file
    document: Document = parser.parse(data)
                         ^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/spdx_tools/spdx/parser/tagvalue/parser.py", line 524, in parse
    self.yacc.parse(text, lexer=self.lex)
  File "/opt/homebrew/lib/python3.11/site-packages/ply/yacc.py", line 333, in parse
    return self.parseopt_notrack(input, lexer, debug, tracking, tokenfunc)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/ply/yacc.py", line 1120, in parseopt_notrack
    p.callable(pslice)
  File "/opt/homebrew/lib/python3.11/site-packages/spdx_tools/spdx/parser/tagvalue/parser.py", line 236, in p_license
    p[0] = get_spdx_licensing().parse(p[1])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/license_expression/__init__.py", line 540, in parse
    tokens = list(self.tokenize(
             ^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/license_expression/__init__.py", line 604, in tokenize
    for token in tokens:
  File "/opt/homebrew/lib/python3.11/site-packages/license_expression/__init__.py", line 997, in replace_with_subexpression_by_license_symbol
    for token_group in token_groups:
  File "/opt/homebrew/lib/python3.11/site-packages/license_expression/__init__.py", line 936, in build_token_groups_for_with_subexpression
    tokens = list(tokens)
             ^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/license_expression/__init__.py", line 598, in <genexpr>
    tokens = (t for t in tokens if t.string and t.string.strip())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/license_expression/__init__.py", line 922, in build_symbols_from_unknown_tokens
    for symtok in build_token_with_symbol():
  File "/opt/homebrew/lib/python3.11/site-packages/license_expression/__init__.py", line 902, in build_token_with_symbol
    toksym = LicenseSymbol(string)
             ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/lib/python3.11/site-packages/license_expression/__init__.py", line 1214, in __init__
    raise ExpressionError(
license_expression.ExpressionError: Invalid license key: the valid characters are: letters and numbers, underscore, dot, colon or hyphen signs and spaces: 'LicenseRef-foo/bar'