anchor.diff:    wget \
     cmake \
     python \
  -  python-pip \
  -  python-dev \
  +  python3 \
  +  python3-pip \
  +  python3-dev \
     g++ \
     libtbb-dev \
     libgl1-mesa-dev \
     libglu1-mesa-dev \
     libxt-dev
   
  -RUN pip install -U pip && \
  -  pip install numpy
  +RUN pip3 install -U pip && \
  +  pip3 install numpy
   
   # Build and install ninja.
   ARG NINJA_VERSION=v1.7.2
  
positive.code:     -DVTK_PYTHON_FULL_THREADSAFE:BOOL=ON \
      -DVTK_NO_PYTHON_THREADS:BOOL=OFF \
      -DQt5_DIR:PATH=/usr/local/Qt-5.8.0/lib/cmake/Qt5 \
      ../paraview && \
    cmake --build . && \
    cd .. && \
  
negative.code:     -DBUILD_EXAMPLES:BOOL=OFF \
      -DBUILD_SHARED_LIBS:BOOL=ON \
      -DCMAKE_INSTALL_PREFIX:PATH=/opt/itk \
      -DPYTHON_EXECUTABLE:PATH=/usr/bin/python3 \
      ../ITK && \
    cmake --build . --target install && \
    cd .. && \
  