[BUG] KeyError when running QNode(qfun, dev)(graph) with graph an instance of networkx Graph object

[simidzija]

Expected behavior

Let qfun take a networkx Graph as an argument. When I call QNode(qfun, dev)(graph) I expect not to get an error because no error occurs for arguments of different types (including various non numeric types).

Actual behavior

Instead when I run QNode(qfun, dev)(graph) I get KeyError: 'networkx'.

Additional information

No response

Source code

import pennylane as qml
import networkx as nx

def circuit(graph):
    return qml.state()

graph = nx.Graph()
qml.QNode(circuit, dev)(graph)

Tracebacks

Traceback (most recent call last):
  File "/Users/petar/Documents/graph_states/new.py", line 11, in <module>
    circuit(x)
  File "/opt/miniconda3/envs/qml/lib/python3.11/site-packages/pennylane/workflow/qnode.py", line 987, in __call__
    return self._impl_call(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/miniconda3/envs/qml/lib/python3.11/site-packages/pennylane/workflow/qnode.py", line 973, in _impl_call
    interface = INTERFACE_MAP[interface]
                ~~~~~~~~~~~~~^^^^^^^^^^^
KeyError: 'networkx'

System information

Name: PennyLane
Version: 0.39.0
Summary: PennyLane is a cross-platform Python library for quantum computing, quantum machine learning, and quantum chemistry. Train a quantum computer the same way as a neural network.
Home-page: https://github.com/PennyLaneAI/pennylane
Author: 
Author-email: 
License: Apache License 2.0
Location: /opt/miniconda3/envs/qml/lib/python3.11/site-packages
Requires: appdirs, autograd, autoray, cachetools, networkx, numpy, packaging, pennylane-lightning, requests, rustworkx, scipy, toml, typing-extensions
Required-by: PennyLane_Lightning

Platform info:           macOS-15.1-arm64-arm-64bit
Python version:          3.11.10
Numpy version:           1.26.4
Scipy version:           1.14.1
Installed devices:
- default.clifford (PennyLane-0.39.0)
- default.gaussian (PennyLane-0.39.0)
- default.mixed (PennyLane-0.39.0)
- default.qubit (PennyLane-0.39.0)
- default.qutrit (PennyLane-0.39.0)
- default.qutrit.mixed (PennyLane-0.39.0)
- default.tensor (PennyLane-0.39.0)
- null.qubit (PennyLane-0.39.0)
- reference.qubit (PennyLane-0.39.0)
- lightning.qubit (PennyLane_Lightning-0.39.0)

Existing GitHub issues

• I have searched existing GitHub issues to make sure the issue does not already exist.