def check_membership(user, group)
      raise JSS::NoSuchItemError, 'LDAPServer not yet saved in the JSS' unless @in_jss
      self.class.check_membership @id, user, group, api: @api
    end
def check_membership(user, group)
      raise JSS::NoSuchItemError, 'LDAPServer not yet saved in the JSS' unless @in_jss
      self.class.check_membership @id, user, group, api: @api
    end
@param user[String] the username to check for memebership in the group

 @param group[String] the group name to see if the user is a member

 @return [Boolean, nil] is the user a member? Nil if unable to check