How to Check User Exist in SharePoint User Group

// Function to check user exist in SharePoint Group
public bool CheckUserGroup(string groupName, string userName)
    {
        bool userFound = false;
        SPFieldUserValueCollection userCols = new SPFieldUserValueCollection();
        SPSecurity.RunWithElevatedPrivileges(delegate()
        {
            SPSite objSite = new SPSite(SPContext.Current.Web.Url);
            SPWeb objWeb = objSite.OpenWeb();
            SPGroup spGroup = objWeb.SiteGroups[groupName];
            foreach(SPUser groupUser in spGroup.Users)
            {
                if (groupUser.Name == userName)
                {
                    userFound = true;
                    break;
                }
            }
        });
        return userFound;
    }
    // Calling function
bool isUserAdmin = CheckUserGroup("Administrator", "Ramakrishna Basagalla");