How to use the dockerfile.Dockerfile function in dockerfile

import shutil
from dockerfile import Dockerfile

class Windows(Dockerfile):
    def __init__(self, arch, linktype='static'):
        self.arch = arch
        name = 'windows-{}'.format(arch)
        mxe_prefix = '{}-w64-mingw32.{}'.format(arch, linktype)
        configuration_file = 'configuration-windows-{}-{}.cmake'.format(arch, linktype)
        self.cmake_binary = mxe_prefix + '-cmake'
        self.os_family = 'windows'

        substitutions = {
            'CMAKE_BIN': self.cmake_binary,
            'MXE_PREFIX': mxe_prefix,
            'ARCH': arch,
            'LINKTYPE': linktype,
            'CMAKE_CACHE_INIT': configuration_file,
            'PACKAGE_SYSTEM_NAME': 'Windows-' + arch,
        }

import shutil
from dockerfile import Dockerfile


class LinuxBase(Dockerfile):
    def __init__(self, snippet, flavour, version, arch, extra_snippets = [], extra_substitutions={}):
        self.flavour = flavour
        self.version = version
        self.arch = arch
        name = '{}-{}-{}'.format(flavour, version, arch)
        base_image = '{}:{}'.format(flavour, version)
        config_name = '{}-{}'.format(flavour, version)
        self.cmake_binary = 'cmake'
        self.os_family = 'linux'

        if arch != 'x86_64':
            base_image = arch + '/' + base_image

        configuration_file = 'configuration-{}.cmake'.format(config_name)

        substitutions = {