PanicError when duplicate layers are passed to find_illegal_dependencies

[seddonym]

E.g.

>>> import grimp
>>> g = grimp.build_graph("grimp")
>>> graph.find_illegal_dependencies_for_layers(layers=("grimp.domain", "grimp.domain"))
thread '<unnamed>' panicked at src/importgraph.rs:144:63:
no entry found for key
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/.../grimp/adaptors/graph.py", line 372, in find_illegal_dependencies_for_layers
    return _layers.find_illegal_dependencies(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/.../grimp/adaptors/_layers.py", line 46, in find_illegal_dependencies
    rust_package_dependency_tuple = rust.find_illegal_dependencies(
                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
pyo3_runtime.PanicException: no entry found for key