Minor fixes

miplearn/solvers/learning.py

@@ -7,7 +7,6 @@ import logging
 import os
 import pickle
 import tempfile
-from copy import deepcopy
 from typing import Optional, List, Any, IO, cast, BinaryIO, Union, Callable, Dict
 
 from p_tqdm import p_map

miplearn/solvers/tests/test_internal_solver.py

@@ -7,7 +7,6 @@ from io import StringIO
 from warnings import warn
 
 import pyomo.environ as pe
-from pytest import raises
 
 from miplearn.solvers import RedirectOutput
 from miplearn.solvers.gurobi import GurobiSolver