anchor.diff:                              hkp://keyserver.ubuntu.com:80 \
                               pgp.mit.edu) ; do gpg --no-tty --keyserver "$server" --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4 && s=0 && break || s=$?; done; (exit $s)
   
  -RUN curl -o /usr/local/bin/gosu -SL "https://github.com/tianon/gosu/releases/download/1.10/gosu-$(dpkg --print-architecture)" \
  -    && curl -o /usr/local/bin/gosu.asc -SL "https://github.com/tianon/gosu/releases/download/1.10/gosu-$(dpkg --print-architecture).asc" \
  +RUN curl -o /usr/local/bin/gosu -sSL "https://github.com/tianon/gosu/releases/download/1.10/gosu-$(dpkg --print-architecture)" \
  +    && curl -o /usr/local/bin/gosu.asc -sSL "https://github.com/tianon/gosu/releases/download/1.10/gosu-$(dpkg --print-architecture).asc" \
       && gpg --verify /usr/local/bin/gosu.asc \
       && rm /usr/local/bin/gosu.asc \
       && chmod +x /usr/local/bin/gosu
  
positive.code: ARG PYTHON_IMAGE
  FROM ${PYTHON_IMAGE}
  
  RUN apt-get update && apt-get -y --no-install-recommends install \
                                                              ca-certificates \
                                                              curl \
                                                              netcat \
  
negative.code: RUN if command -v pypy3; then ln -s $(command -v pypy3) /usr/local/bin/python; elif command -v pypy; then ln -s $(command -v pypy) /usr/local/bin/python; fi
  
  # pre-install base requirements
  RUN python -m pip install --progress-bar off -U pip && pip install --progress-bar off -r /requirements-base.txt
  
  RUN chmod +x /usr/local/bin/entrypoint.sh
  
  