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

for more information, see https://pre-commit.ci

src/qibotn/backends/quimb.py

@@ -1,15 +1,14 @@
+import numpy as np
 from qibo.backends.numpy import NumpyBackend
 from qibo.config import raise_error
 from qibo.result import QuantumState
-import numpy as np
 
 
 class QuimbBackend(NumpyBackend):
 
     def __init__(self, runcard):
         super().__init__()
         import quimb  # pylint: disable=import-error
-
 
         if runcard is not None:
             self.MPI_enabled = runcard.get("MPI_enabled", False)
@@ -76,7 +75,6 @@ def execute_circuit(
                 NotImplementedError, "QiboTN quimb backend cannot support expectation"
             )
 
-
         if self.MPI_enabled == True:
             state, rank = eval.dense_vector_tn_mpi_qu(
                 circuit.to_qasm(),
@@ -92,7 +90,6 @@ def execute_circuit(
                 circuit.to_qasm(), initial_state, self.mps_opts, backend="numpy"
             )
 
-
         if return_array:
             return state.flatten()
         else: