How to use the six.iteritems function in six

def merge_api_rest_dicts(self):
        for package, path_type_tuple in six.iteritems(self.api_package_spec_dict):
            if package in self.rest_package_spec_dict:
                # Transitive dependency between function calls
                self.__merge_type_dicts(self.rest_package_spec_dict[package][1], path_type_tuple[1])
                self.__merge_path_dicts(self.rest_package_spec_dict[package][0], path_type_tuple[0])
            else:
                self.rest_package_spec_dict[package] = path_type_tuple
        return self.rest_package_spec_dict

def to_dict(self):
        """Returns the model properties as a dict"""
        result = {}

        for attr, _ in six.iteritems(self.openapi_types):
            value = getattr(self, attr)
            if isinstance(value, list):
                result[attr] = list(map(
                    lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                    value
                ))
            elif hasattr(value, "to_dict"):
                result[attr] = value.to_dict()
            elif isinstance(value, dict):
                result[attr] = dict(map(
                    lambda item: (item[0], item[1].to_dict())
                    if hasattr(item[1], "to_dict") else item,
                    value.items()
                ))
            else:
                result[attr] = value

def to_dict(self):
        """
        Returns the model properties as a dict
        """
        result = {}

        for attr, _ in iteritems(self.swagger_types):
            value = getattr(self, attr)
            if isinstance(value, list):
                result[attr] = list(map(
                    lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                    value
                ))
            elif hasattr(value, "to_dict"):
                result[attr] = value.to_dict()
            elif isinstance(value, dict):
                result[attr] = dict(map(
                    lambda item: (item[0], item[1].to_dict())
                    if hasattr(item[1], "to_dict") else item,
                    value.items()
                ))
            else:
                result[attr] = value

def _flatten(data, prefix=None):
    """Flatten a dict, using name as a prefix for the keys of dict.

    >>> _flatten('cpu_info', {'arch':'x86_64'})
    [('cpu_info_arch': 'x86_64')]

    """
    if isinstance(data, dict):
        for key, value in six.iteritems(data):
            new_key = '%s_%s' % (prefix, key) if prefix else key
            if isinstance(value, (dict, list)):
                for item in _flatten(value, new_key):
                    yield item
            else:
                yield new_key, value
    else:
        yield prefix, data

def to_dict(self):
        """Returns the model properties as a dict"""
        result = {}

        for attr, _ in six.iteritems(self.swagger_types):
            value = getattr(self, attr)
            if isinstance(value, list):
                result[attr] = list(map(
                    lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                    value
                ))
            elif hasattr(value, "to_dict"):
                result[attr] = value.to_dict()
            elif isinstance(value, dict):
                result[attr] = dict(map(
                    lambda item: (item[0], item[1].to_dict())
                    if hasattr(item[1], "to_dict") else item,
                    value.items()
                ))
            else:
                result[attr] = value

def to_dict(self):
        """Returns the model properties as a dict"""
        result = {}

        for attr, _ in six.iteritems(self.swagger_types):
            value = getattr(self, attr)
            if isinstance(value, list):
                result[attr] = list(map(
                    lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                    value
                ))
            elif hasattr(value, "to_dict"):
                result[attr] = value.to_dict()
            elif isinstance(value, dict):
                result[attr] = dict(map(
                    lambda item: (item[0], item[1].to_dict())
                    if hasattr(item[1], "to_dict") else item,
                    value.items()
                ))
            else:
                result[attr] = value

def to_dict(self):
        """
        Returns the model properties as a dict
        """
        result = {}

        for attr, _ in iteritems(self.swagger_types):
            value = getattr(self, attr)
            if isinstance(value, list):
                result[attr] = list(map(
                    lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                    value
                ))
            elif hasattr(value, "to_dict"):
                result[attr] = value.to_dict()
            elif isinstance(value, dict):
                result[attr] = dict(map(
                    lambda item: (item[0], item[1].to_dict())
                    if hasattr(item[1], "to_dict") else item,
                    value.items()
                ))
            else:
                result[attr] = value

def to_dict(self):
        """
        Returns the model properties as a dict
        """
        result = {}

        for attr, _ in iteritems(self.swagger_types):
            value = getattr(self, attr)
            if isinstance(value, list):
                result[attr] = list(map(
                    lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                    value
                ))
            elif hasattr(value, "to_dict"):
                result[attr] = value.to_dict()
            elif isinstance(value, dict):
                result[attr] = dict(map(
                    lambda item: (item[0], item[1].to_dict())
                    if hasattr(item[1], "to_dict") else item,
                    value.items()
                ))
            else:
                result[attr] = value

def to_dict(self):
        # type: () -> Dict[str, object]
        """Returns the model properties as a dict"""
        result = {}  # type: Dict

        for attr, _ in six.iteritems(self.deserialized_types):
            value = getattr(self, attr)
            if isinstance(value, list):
                result[attr] = list(map(
                    lambda x: x.to_dict() if hasattr(x, "to_dict") else
                    x.value if isinstance(x, Enum) else x,
                    value
                ))
            elif isinstance(value, Enum):
                result[attr] = value.value
            elif hasattr(value, "to_dict"):
                result[attr] = value.to_dict()
            elif isinstance(value, dict):
                result[attr] = dict(map(
                    lambda item: (item[0], item[1].to_dict())
                    if hasattr(item[1], "to_dict") else
                    (item[0], item[1].value)

timeout. It can also be a pair (tuple) of
                                 (connection, read) timeouts.
        :return: tuple(object, status_code(int), headers(HTTPHeaderDict))
                 If the method is called asynchronously,
                 returns the request thread.
        """

        local_var_params = locals()

        all_params = []  # noqa: E501
        all_params.append('async_req')
        all_params.append('_return_http_data_only')
        all_params.append('_preload_content')
        all_params.append('_request_timeout')

        for key, val in six.iteritems(local_var_params['kwargs']):
            if key not in all_params:
                raise ApiTypeError(
                    "Got an unexpected keyword argument '%s'"
                    " to method private_get_email_language_get" % key
                )
            local_var_params[key] = val
        del local_var_params['kwargs']

        collection_formats = {}

        path_params = {}

        query_params = []

        header_params = {}