'Determine if client authentication is required for current request.
According to the rfc6749, client authentication is required in the following cases:
- Resource Owner Password Credentials Grant, when Client type is Confidential or when
Client was issued client credentials or whenever Client provided client
authentication, see `Section 4.3.2`_.
- Authorization Code Grant, when Client type is Confidential or when Client was issued
client credentials or whenever Client provided client authentication,
see `Section 4.1.3`_.
- Refresh Token Grant, when Client type is Confidential or when Client was issued
client credentials or whenever Client provided client authentication, see
`Section 6`_
:param request: oauthlib.common.Request
:rtype: True or False
Method is used by:
- Authorization Code Grant
- Resource Owner Password Credentials Grant
- Refresh Token Grant
.. _`Section 4.3.2`: http://tools.ietf.org/html/rfc6749#section-4.3.2
.. _`Section 4.1.3`: http://tools.ietf.org/html/rfc6749#section-4.1.3
.. _`Section 6`: http://tools.ietf.org/html/rfc6749#section-6'

def client_authentication_required(self, request, *args, **kwargs):

    return True
