class Registry(object):
    def __init__(self, key: Union[None, str, int] = None, computer_name: Optional[str] = None):
        """
        The Registry Class, to create the registry object.
        If a key is passed, a connection to the hive is established.

        Parameter
        ---------

        key:
            the predefined handle to connect to,
            or a key string with the hive as the first part (everything else but the hive will be ignored)
            or None (then no connection will be established)
        computer_name:
            the name of the remote computer, of the form r"\\computer_name" or "computer_name". If None, the local computer is used.

        Exceptions
        ----------
            RegistryNetworkConnectionError      if we can not reach target computer
            RegistryHKeyError                   if we can not connect to the hive
            winreg.ConnectRegistry              auditing event

        Examples
        --------

        >>> # just create the instance without connection
        >>> registry = Registry()

        >>> # test connect at init:
        >>> registry = Registry('HKCU')

        >>> # test invalid hive as string
        >>> Registry()._reg_connect('SPAM')
        Traceback (most recent call last):
            ...
        lib_registry.RegistryHKeyError: invalid KEY: "SPAM"

        >>> # test invalid hive as integer
        >>> Registry()._reg_connect(42)
        Traceback (most recent call last):
            ...
        lib_registry.RegistryHKeyError: invalid HIVE KEY: "42"

        >>> # test invalid computer to connect
        >>> Registry()._reg_connect(winreg.HKEY_LOCAL_MACHINE, computer_name='some_unknown_machine')
        Traceback (most recent call last):
            ...
        lib_registry.RegistryNetworkConnectionError: The network address "some_unknown_machine" is invalid

        >>> # test invalid network Path
        >>> Registry()._reg_connect(winreg.HKEY_LOCAL_MACHINE, computer_name=r'localhost\\ham\\spam')
        Traceback (most recent call last):
            ...
        lib_registry.RegistryNetworkConnectionError: The network path to "localhost\\ham\\spam" was not found

        """

def create_key(self, key: Union[str, int], sub_key: str = '', exist_ok: bool = True, parents: bool = False) -> winreg.HKEYType:
    """
    Creates a Key, and returns a Handle to the new key


    Parameter
    ---------
    key
      either a predefined HKEY_* constant,
      a string containing the root key,
      or an already open key
    sub_key
      a string with the desired subkey relative to the key
    exist_ok
      bool, default = True
    parents
      bool, default = false


    Exceptions
    ----------
    RegistryKeyCreateError
        if we can not create the key


    Examples
    --------

    >>> # Setup
    >>> registry = Registry()
    >>> # create a key
    >>> registry.create_key(r'HKCU\\Software')
    <...PyHKEY object at ...>

    >>> # create an existing key, with exist_ok = True
    >>> registry.create_key(r'HKCU\\Software\\lib_registry_test', exist_ok=True)
    <...PyHKEY object at ...>

    >>> # create an existing key, with exist_ok = False (parent existing)
    >>> registry.create_key(r'HKCU\\Software\\lib_registry_test', exist_ok=False)
    Traceback (most recent call last):
        ...
    lib_registry.RegistryKeyCreateError: can not create key, it already exists: HKEY_CURRENT_USER...lib_registry_test

    >>> # create a key, parent not existing, with parents = False
    >>> registry.create_key(r'HKCU\\Software\\lib_registry_test\\a\\b', parents=False)
    Traceback (most recent call last):
        ...
    lib_registry.RegistryKeyCreateError: can not create key, the parent key to "HKEY_CURRENT_USER...b" does not exist

    >>> # create a key, parent not existing, with parents = True
    >>> registry.create_key(r'HKCU\\Software\\lib_registry_test\\a\\b', parents=True)
    <...PyHKEY object at ...>

    >>> # TEARDOWN
    >>> registry.delete_key(r'HKCU\\Software\\lib_registry_test', delete_subkeys=True)

    """

def delete_key(self, key: Union[str, int], sub_key: str = '', missing_ok: bool = False, delete_subkeys: bool = False) -> None:
    """
    deletes the specified key, this method can delete keys with subkeys.
    If the method succeeds, the entire key, including all of its values, is removed.

    Parameter
    ---------
    key
      either a predefined HKEY_* constant,
      a string containing the root key,
      or an already open key
    sub_key
      a string with the desired subkey relative to the key
    missing_ok
      bool, default = False
    delete_subkeys
      bool, default = False

    Exceptions
    ----------
        RegistryKeyDeleteError  If the key does not exist,
        RegistryKeyDeleteError  If the key has subkeys and delete_subkeys = False

    >>> # Setup
    >>> registry = Registry()
    >>> # create a key, parent not existing, with parents = True
    >>> registry.create_key(r'HKCU\\Software\\lib_registry_test\\a\\b', parents=True)
    <...PyHKEY object at ...>

    >>> # Delete a Key
    >>> assert registry.key_exist(r'HKCU\\Software\\lib_registry_test\\a\\b') == True
    >>> registry.delete_key(r'HKCU\\Software\\lib_registry_test\\a\\b')
    >>> assert registry.key_exist(r'HKCU\\Software\\lib_registry_test\\a\\b') == False

    >>> # Try to delete a missing Key
    >>> registry.delete_key(r'HKCU\\Software\\lib_registry_test\\a\\b')
    Traceback (most recent call last):
        ...
    lib_registry.RegistryKeyDeleteError: can not delete key none existing key ...

    >>> # Try to delete a missing Key, missing_ok = True
    >>> registry.delete_key(r'HKCU\\Software\\lib_registry_test\\a\\b')
    Traceback (most recent call last):
        ...
    lib_registry.RegistryKeyDeleteError: can not delete key none existing key ...

    >>> # Try to delete a Key with subkeys
    >>> registry.delete_key(r'HKCU\\Software\\lib_registry_test')
    Traceback (most recent call last):
        ...
    lib_registry.RegistryKeyDeleteError: can not delete none empty key ...

    >>> # Try to delete a Key with subkeys, delete_subkeys = True
    >>> registry.delete_key(r'HKCU\\Software\\lib_registry_test', delete_subkeys=True)
    >>> assert registry.key_exist(r'HKCU\\Software\\lib_registry_test') == False

    >>> # Try to delete a Key with missing_ok = True
    >>> registry.delete_key(r'HKCU\\Software\\lib_registry_test', missing_ok=True)

    """

def key_exist(self, key: Union[str, int], sub_key: str = '') -> bool:
    """
    True if the given key exists

    Parameter
    ---------
    key
      either a predefined HKEY_* constant,
      a string containing the root key,
      or an already open key

    sub_key
      a string with the desired subkey relative to the key


    Examples
    --------

    >>> Registry().key_exist(r'HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion')
    True
    >>> Registry().key_exist(r'HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\DoesNotExist')
    False

    """