def list_roles
      response = oauth_access_token.get('/v1/roles')
      response.parsed.collect { |parsed_role| Role.new(parsed_role) }
    end
def list_roles
      response = oauth_access_token.get('/v1/roles')
      response.parsed.collect { |parsed_role| Role.new(parsed_role) }
    end
Return all user roles from the remote service
 @return [Array<G5AuthenticationClient::Role>]