[source,vbnet]
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Imports System.Diagnostics.CodeAnalysis
Imports System.Runtime.CompilerServices
Imports System.Text.RegularExpressions

Module Program
    <Extension>
    Function RemoveVowels(Value As String) As String
        If Value Is Nothing Then
            Return Nothing
        End If
        Return Regex.Replace(Value, "[aeoui]*", "", RegexOptions.IgnoreCase)
    End Function

    Sub Main()
        Dim StrValue As String = Nothing
        Console.WriteLine(StrValue.RemoveVowels()) ' Compliant: 'RemoveVowels' is an extension method
    End Sub
End Module
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