Support for CustomCode-Types?

[carstencodes]

Hi,

I'm using the library for quite a while and it is really cool. Unfortunately, I do have a project now which uses Enums and dataclasses.

The following code describes briefly what I'm doing:

from enum import Enum, auto
from dataclasses import dataclass, field, asdict
from dicttoxml import dicttoxml

class MyEnum:
    A = auto()
    B = auto()
    C = auto()

@dataclass
class MyDc
    x: str = field()
    y: int = field()
    z: MyEnum = field()

dc = MyDc()
dt = asdict(dc)
xml = dicttoxml(dt)

Creating a json file from the dictionary is possible, when using a customized JSONEncoder instance, which is handed over to the encode function.

With this issue I suggest the extension of the dicttoxml method:

def dicttoxml(obj, root=True, custom_root='root', ids=False, attr_type=True,
    item_func=default_item_func, cdata=False, *, converter_func=convert)

This way, a custom converter function can be used to serialize custom data types like Enums or special objects:

def convert_with_enum(obj, ids, attr_type, item_func, cdata, parent='root'):
    if isinstance(obj, Enum):
          item_name = item_func(parent)
          return convert_kv(item_name, obj.name, attr_type, cdata)
    return convert(obj, ids, attr_type, item_func, cdata, parent)

I can submit a pull request, if you consider this issue as valueable.

Regards Carsten