How to use the fastjsonschema.draft04.CodeGeneratorDraft04 function in fastjsonschema

def _get_code_generator_class(schema):
    # Schema in from draft-06 can be just the boolean value.
    if isinstance(schema, dict):
        schema_version = schema.get('$schema', '')
        if 'draft-04' in schema_version:
            return CodeGeneratorDraft04
        if 'draft-06' in schema_version:
            return CodeGeneratorDraft06
    return CodeGeneratorDraft07

from .draft04 import CodeGeneratorDraft04, JSON_TYPE_TO_PYTHON_TYPE
from .exceptions import JsonSchemaDefinitionException
from .generator import enforce_list


class CodeGeneratorDraft06(CodeGeneratorDraft04):
    FORMAT_REGEXS = dict(CodeGeneratorDraft04.FORMAT_REGEXS, **{
        'json-pointer': r'^(/(([^/~])|(~[01]))*)*\Z',
        'uri-reference': r'^(\w+:(\/?\/?))?[^#\\\s]*(#[^\\\s]*)?\Z',
        'uri-template': (
            r'^(?:(?:[^\x00-\x20\"\'<>%\\^`{|}]|%[0-9a-f]{2})|'
            r'\{[+#./;?&=,!@|]?(?:[a-z0-9_]|%[0-9a-f]{2})+'
            r'(?::[1-9][0-9]{0,3}|\*)?(?:,(?:[a-z0-9_]|%[0-9a-f]{2})+'
            r'(?::[1-9][0-9]{0,3}|\*)?)*\})*\Z'
        ),
    })

    def __init__(self, definition, resolver=None, formats={}):
        super().__init__(definition, resolver, formats)
        self._json_keywords_to_function.update((
            ('exclusiveMinimum', self.generate_exclusive_minimum),
            ('exclusiveMaximum', self.generate_exclusive_maximum),