System.Security.Permissions.IsolatedStorageFilePermission.IsSubsetOf C# (CSharp) Method

        public override bool IsSubsetOf(IPermission target)
        {
            if (target == null)
            {
                return ((m_userQuota == 0) &&
                        (m_machineQuota == 0) &&
                        (m_expirationDays == 0) &&
                        (m_permanentData == false) &&
                        (m_allowed == IsolatedStorageContainment.None));
            }

            try
            {
                IsolatedStorageFilePermission operand = (IsolatedStorageFilePermission)target;

                if (operand.IsUnrestricted())
                    return true;

                return ((operand.m_userQuota >= m_userQuota) &&
                        (operand.m_machineQuota >= m_machineQuota) &&
                        (operand.m_expirationDays >= m_expirationDays) &&
                        (operand.m_permanentData || !m_permanentData) &&
                        (operand.m_allowed >= m_allowed));
            }
            catch (InvalidCastException)
            {
                throw new 
                    ArgumentException(
                                    String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Argument_WrongType"), this.GetType().FullName)
                                     );
            }                

        }
        

		public void IsSubsetOf_DifferentPermissions ()
		{
			IsolatedStorageFilePermission a = new IsolatedStorageFilePermission (PermissionState.None);
			SecurityPermission b = new SecurityPermission (PermissionState.None);
			a.IsSubsetOf (b);
		}