Failure to retrieve FakeBackend from FakeProviderforBackendV2

[arthurostrauss]

Describe the bug
There is an error occurring when trying to retrieve a FakeBackendV2 from the FakeProviderForBackendV2object through FakeProviderForBackendV2.backend(backend_name) method.

The error raised is:
filtered_backends = [backend for backend in self._backends if backend.name() == name]

TypeError: 'str' object is not callable

Steps to reproduce

1. declare a FakeProviderForBackendV2 instance and a valid backend name, e.g. 'fake_jakarta'
2. Call method backend()

Expected behavior
Should return a FakeBackend object

Suggested solutions
Adapt the code to the BackendV2 interface, where the name of the FakeBackend is an attribute and no longer a method (name instead of name())

Additional Information
It would be good to also adapt the backends attribute to fit the retrieval of backend through FakeProvider.get_backend() method as well.

• qiskit-ibm-runtime version: 0.19.2
• Python version: 3.11
• Operating system: Mac OS Sonoma 14.3