diff --git a/.github/workflows/prepare_environment.sh b/.github/workflows/prepare_environment.sh
deleted file mode 100755
index 892a886..0000000
--- a/.github/workflows/prepare_environment.sh
+++ /dev/null
@@ -1,11 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-
-PYTHON_VERSION=$1
-
-conda create --quiet -c conda-forge -c free -n test-env \
-    python="$PYTHON_VERSION" \
-    "pytest>=4.6" pylint pytest-cov pytest-mock pycodestyle \
-    mock setuptools setuptools_scm wheel
-source "${CONDA}/bin/activate" test-env
-pip install ".[testing]"
diff --git a/.github/workflows/python2-3-app.yml b/.github/workflows/python2-3-app.yml
index 764e6ed..52f1cd5 100644
--- a/.github/workflows/python2-3-app.yml
+++ b/.github/workflows/python2-3-app.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.event_name != 'push'
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - uses: actions/setup-python@v2
       with:
         python-version: '3.9'
@@ -27,20 +27,18 @@ jobs:
           - 3.9
 
     steps:
-    - uses: actions/checkout@v2
-    - name: Set up Python
-      uses: actions/setup-python@v2
-
-    - uses: actions/checkout@v2
-    - name: Prepare environment
-      run: .github/workflows/prepare_environment.sh ${{ matrix.python_version }}
+    - uses: actions/checkout@v4
+    - name: prepare environment
+      run: |
+        conda config --set add_pip_as_python_dependency false
+        conda create -c conda-forge -n db12 python=${{ matrix.python_version }}
 
     - name: Run pylint
       run: |
-        . "${CONDA}/bin/activate" test-env
+        eval "$(conda shell.bash hook)" && conda activate db12
         pylint -E src/db12/ tests/
 
     - name: Run pytest
       run: |
-        . "${CONDA}/bin/activate" test-env
+        eval "$(conda shell.bash hook)" && conda activate db12
         pytest tests
diff --git a/src/db12/benchmark.py b/src/db12/benchmark.py
index 30d44d5..82a11ff 100644
--- a/src/db12/benchmark.py
+++ b/src/db12/benchmark.py
@@ -64,7 +64,7 @@ def single_dirac_benchmark(iterations_num=1, measured_copies=None, correction=Tr
 
         it_1 += 1
 
-    cput = sum(end[:4]) - sum(start[:4])
+    cput = sum(end[:4]) - sum(start[:4])  # pylint: disable=used-before-assignment
     wall = end[4] - start[4]
 
     if not cput: