[pre-commit.ci] auto fixes from pre-commit.com hooks

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src/qibotn/backends/quimb.py

@@ -1,4 +1,3 @@
-from qibo.backends.numpy import NumpyBackend
 from qibo.config import raise_error
 from qibo.result import QuantumState
 
@@ -38,7 +37,6 @@ class QuimbBackend(QibotnBackend):
         self.platform = "QuimbBackend"
         self.versions["quimb"] = self.quimb.__version__
 
-
     def execute_circuit(
         self, circuit, initial_state=None, nshots=None, return_array=False
     ):  # pragma: no cover