Docker contain opens directly into specified conda environment - docker

Question

I have a Docker container that has two conda environments in it. One is used the vast majority of the time so I would like to automatically start in that environment (currently in starts in the base environment). Based on this website I tried by adding this to the end of my Dockerfile:
# Activate env
SHELL ["conda", "run", "-n", "py3", "/bin/bash", "-c"]
ENTRYPOINT ["conda", "run", "-n", "py3", "python", "pass.py"]
where run.py just contains print("hello world").
This caused the script to run but the docker container does not remain open after I run the docker container, although it does when I remove these lines. How do I get the container to open and stay open in a specified environment?
My Dockerfile looks like this:
FROM nvidia/cuda:10.1-cudnn7-devel-centos7
WORKDIR /app/
COPY ./*.* ./
ENV CONDA_DIR "/opt/conda"
ENV PATH "$CONDA_DIR"/bin:$PATH
ONBUILD ENV PATH "$CONDA_DIR"/bin:$PATH
RUN \
yum -y install epel-release && \
yum -y update && \
yum install -y \
bzip2 \
curl \
which \
libXext \
libSM \
libXrender \
git \
cuda-nvcc-10-1 \
openssh-server \
postgresql-devel \
yum clean all && rm -rf /var/cache/yum/*
RUN CONDA_VERSION="4.7.12" && \
curl -L \
https://repo.continuum.io/miniconda/Miniconda3-${CONDA_VERSION}-Linux-x86_64.sh -o miniconda.sh && \
mkdir -p "$CONDA_DIR" && \
bash miniconda.sh -f -b -p "$CONDA_DIR" && \
echo "export PATH=$CONDA_DIR/bin:\$PATH" > /etc/profile.d/conda.sh && \
rm miniconda.sh && \
conda config --add channels conda-forge && \
conda config --set auto_update_conda False && \
pip install --upgrade pip && \
rm -rf /root/.cache/pip/*
RUN conda env create -f py2_env.yaml
RUN conda env create -f py3_env.yaml
# Activate env
SHELL ["conda", "run", "-n", "py3", "/bin/bash", "-c"]
ENTRYPOINT ["conda", "run", "-n", "py3", "python", "pass.py"]