' Check whether a given regular expression is in valid format' Examples:'   Debug.WriteLine(IsValidRegularExpression("^(((d{3}) ' ?)|(d{3}-))?d{3}-d{4}$")) ' => True'   Debug.WriteLine(IsValidRegularExpression("^[|)$")) ' => FalseFunction IsValidRegularExpression(ByVal regex As String) As Boolean    Try        Dim r As New System.Text.RegularExpressions.Regex(regex)        ' if the line above did not throw an exception, the expression is valid        Return True    Catch ex As Exception        Return False    End TryEnd Function