-virtualenv --system-site-packages -p python3 $PYENV_HOME
-. $PYENV_HOME/bin/activate
-pip install --quiet pylint
-pip install --quiet pep8
+virtualenv --system-site-packages -p ${PYTHON3} "$PYENV_HOME"
+
+set +ux
+# shellcheck disable=SC1090
+. "$PYENV_HOME/bin/activate"
+set -ux
+
+if [ -f "$SRCDIR/dev-requirements.txt" ]; then
+ pip install -r "$SRCDIR/dev-requirements.txt"
+else
+ pip install --quiet black
+ pip install --quiet flake8
+fi
+
+exit_code=0
+
+cd "$SRCDIR"