'Try to find the token for the provided request token key.'

def _get_token(self, oauth_request, token_type='access'):

    token_field = oauth_request.get_parameter('oauth_token')
    token = self.data_store.lookup_token(token_type, token_field)
    if (not token):
        raise OAuthError(('Invalid    %s    token:    %s' % (token_type, token_field)))
    return token
