code: def roles(self, roles_list):
          '''
          Set the roles for the current launch.
  
          Full list of roles can be found here:
          http://www.imsglobal.org/LTI/v1p1/ltiIMGv1p1.html#_Toc319560479
  
          LIS roles include:
          * Student
          * Faculty
          * Member
          * Learner
          * Instructor
          * Mentor
          * Staff
          * Alumni
          * ProspectiveStudent
          * Guest
          * Other
          * Administrator
          * Observer
          * None
          '''
          if roles_list and isinstance(roles_list, list):
              self.roles = [].extend(roles_list)
          elif roles_list and isinstance(roles_list, basestring):
              self.roles = [role.lower() for role in roles_list.split(',')f roles(self, roles_list):
          '''
          Set the roles for the current launch.
  
          Full list of roles can be found here:
          http://www.imsglobal.org/LTI/v1p1/ltiIMGv1p1.html#_Toc319560479
  
          LIS roles include:
          * Student
          * Faculty
          * Member
          * Learner
          * Instructor
          * Mentor
          * Staff
          * Alumni
          * ProspectiveStudent
          * Guest
          * Other
          * Administrator
          * Observer
          * None
          '''
          if roles_list and isinstance(roles_list, list):
              self.roles = [].extend(roles_list)
          elif roles_list and isinstance(roles_list, basestring):
              self.roles = [role.lower() for role in roles_list.split(',')]
docs: Set the roles for the current launch.
  
          Full list of roles can be found here:
          http://www.imsglobal.org/LTI/v1p1/ltiIMGv1p1.html#_Toc319560479
  
          LIS roles include:
          * Student
          * Faculty
          * Member
          * Learner
          * Instructor
          * Mentor
          * Staff
          * Alumni
          * ProspectiveStudent
          * Guest
          * Other
          * Administrator
          * Observer
          * None