Let's try:
echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' > /etc/apt/apt.conf.d/docker-clean ; chown -R root /root/.cache/pip ; export DEBIAN_FRONTEND=noninteractive ; export CLEARML_APT_INSTALL="$CLEARML_APT_INSTALL libsm6 libxext6 libxrender-dev libglib2.0-0" ; [ ! -z $(which git) ] || export CLEARML_APT_INSTALL="$CLEARML_APT_INSTALL git" ; declare LOCAL_PYTHON ; for i in {10..5}; do which python3.$i && python3.$i -m pip --version && export LOCAL_PYTHON=$(which python3.$i) && break ; done ; [ ! -z $LOCAL_PYTHON ] || export CLEARML_APT_INSTALL="$CLEARML_APT_INSTALL python3-pip" ; [ -z "$CLEARML_APT_INSTALL" ] || (apt-get update && apt-get install -y $CLEARML_APT_INSTALL) ; [ ! -z $LOCAL_PYTHON ] || export LOCAL_PYTHON=python3 ; $LOCAL_PYTHON -m pip install -U "pip<20.2" ; $LOCAL_PYTHON -m pip install -U clearml-agent