def __distro(self):
        """Based on the Linux distribution, set values accordingly.  A user
        specified value overrides any defaults."""

        if hpccm.config.g_linux_distro == linux_distro.UBUNTU:
            if not self.__ospackages:
                self.__ospackages = ['ca-certificates', 'file',
                                     'libcurl4-openssl-dev', 'libxml2-dev',
                                     'm4', 'make', 'wget', 'zlib1g-dev']
            self.__runtime_ospackages = ['zlib1g']
        elif hpccm.config.g_linux_distro == linux_distro.CENTOS:
            if not self.__ospackages:
                self.__ospackages = ['ca-certificates', 'file',
                                     'libcurl-devel', 'libxml2-devel', 'm4',
                                     'make', 'wget', 'zlib-devel']
                if self.__check:
                    self.__ospackages.append('diffutils')
            self.__runtime_ospackages = ['zlib']
        else: # pragma: no cover
            raise RuntimeError('Unknown Linux distribution')
Based on the Linux distribution, set values accordingly.  A user
        specified value overrides any defaults.
hpccm/building_blocks/netcdf.py