Callables do not always have a __name__ attribute

[pawamoy]

Describe the bug

    from mkdocs.__main__ import cli as mkdocs
    ctx.run(mkdocs, args=["build", "-s"], title="Building documentation")

  File "/media/data/dev/griffe/__pypackages__/3.7/lib/failprint/formats.py", line 134, in as_python_statement
    return f"{func.__name__}({args_str})"
AttributeError: 'Group' object has no attribute '__name__'

Expected behavior
If no __name__ attribute is present, find another way to get a name 😕