# Buggy code
def delete_value(hive, key, vname=None, use_32bit_registry=False):
    """
    Delete a registry value entry or the default value for a key.

    :param str hive: The name of the hive. Can be one of the following

        - HKEY_LOCAL_MACHINE or HKLM
        - HKEY_CURRENT_USER or HKCU
        - HKEY_USER or HKU
        - HKEY_CLASSES_ROOT or HKCR
        - HKEY_CURRENT_CONFIG or HKCC

    :param str key: The key (looks like a path) to the value name.

    :param str vname: The value name. These are the individual name/data pairs
        under the key. If not passed, the key (Default) value will be deleted.

    :param bool use_32bit_registry: Deletes the 32bit portion of the registry on
        64bit installations. On 32bit machines this is ignored.

    :return: Returns True if successful, None if the value didn't exist, and
        False if unsuccessful
    :rtype: bool

    CLI Example:

    .. code-block:: bash

        salt '*' reg.delete_value HKEY_CURRENT_USER 'SOFTWARE\\Salt' 'version'
    """
    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)
    local_vname = _to_unicode(vname)

    registry = Registry()
    hkey = registry.hkeys[local_hive]
    access_mask = registry.registry_32[use_32bit_registry] | win32con.KEY_ALL_ACCESS

    try:
        handle = win32api.RegOpenKeyEx(hkey, local_key, 0, access_mask)
        win32api.RegDeleteValue(handle, local_vname)
        win32api.RegCloseKey(handle)
        broadcast_change()
        return True
    except Exception as exc:  # pylint: disable=E0602
        if exc.winerror == 2:
            return None
        else:
            log.error(exc, exc_info=True)
            log.error("Hive: %s", local_hive)
            log.error("Key: %s", local_key)
            log.error("ValueName: %s", local_vname)
            log.error("32bit Reg: %s", use_32bit_registry)
            return False


# Traceback (TypeError)
local:
---------
ID: test_reg
Function: reg.present
Name: HKEY_LOCAL_MACHINE\SOFTWARE\salttest\salty\salted
Result: False
Comment: An exception occurred in this state: Traceback (most recent call last):
File "c:\salt\bin\lib\site-packages\salt\state.py", line 1878, in call
**cdata['kwargs'])
File "c:\salt\bin\lib\site-packages\salt\loader.py", line 1823, in wrapper
return f(*args, **kwargs)
File "c:\salt\bin\lib\site-packages\salt\states\reg.py", line 196, in present
vdata_decoded = salt.utils.stringutils.to_unicode(vdata, 'utf-8')
File "c:\salt\bin\lib\site-packages\salt\utils\stringutils.py", line 99, in to_unicode
raise TypeError('expected str, bytes, or bytearray')
TypeError: expected str, bytes, or bytearray

# Fixed code
def delete_value(hive, key, vname=None, use_32bit_registry=False):
    """
    Delete a registry value entry or the default value for a key.

    :param str hive: The name of the hive. Can be one of the following

        - HKEY_LOCAL_MACHINE or HKLM
        - HKEY_CURRENT_USER or HKCU
        - HKEY_USER or HKU
        - HKEY_CLASSES_ROOT or HKCR
        - HKEY_CURRENT_CONFIG or HKCC

    :param str key: The key (looks like a path) to the value name.

    :param str vname: The value name. These are the individual name/data pairs
        under the key. If not passed, the key (Default) value will be deleted.

    :param bool use_32bit_registry: Deletes the 32bit portion of the registry on
        64bit installations. On 32bit machines this is ignored.

    :return: Returns True if successful, None if the value didn't exist, and
        False if unsuccessful
    :rtype: bool

    CLI Example:

    .. code-block:: bash

        salt '*' reg.delete_value HKEY_CURRENT_USER 'SOFTWARE\\Salt' 'version'
    """
    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)
    local_vname = _to_unicode(vname)

    registry = Registry()
    try:
        hkey = registry.hkeys[local_hive]
    except KeyError:
        raise CommandExecutionError("Invalid Hive: {0}".format(local_hive))
    access_mask = registry.registry_32[use_32bit_registry] | win32con.KEY_ALL_ACCESS

    try:
        handle = win32api.RegOpenKeyEx(hkey, local_key, 0, access_mask)
        win32api.RegDeleteValue(handle, local_vname)
        win32api.RegCloseKey(handle)
        broadcast_change()
        return True
    except Exception as exc:  # pylint: disable=E0602
        if exc.winerror == 2:
            return None
        else:
            log.error(exc, exc_info=True)
            log.error("Hive: %s", local_hive)
            log.error("Key: %s", local_key)
            log.error("ValueName: %s", local_vname)
            log.error("32bit Reg: %s", use_32bit_registry)
            return False