How to use the result._internalErrors.append function in result

gen.startDocument()
        gen.startPrefixMapping( 'atom', atom)
        gen.startPrefixMapping( 'tf', tf )

        startElement( gen, atom, 'entry' )
        
        writeElement( gen, atom, 'title', result.constructTitle() )
        writeElement( gen, atom, 'updated', datetime.datetime.now().isoformat() )

        writeElement( gen, tf, 'errorSummary', exitStatusAsString( result.status() ) )

        writeElement( gen, tf, 'host', socket.gethostname() )
        if result._testStart != None:
            writeElement( gen, tf, 'testStart', result._testStart.isoformat() )
        else:
            result._internalErrors.append( "Result generator: no start timestamp found." )

        if result._testEnd != None:
            writeElement( gen, tf, 'testEnd', result._testEnd.isoformat() )
        else:
            result._internalErrors.append( "Result generator: no end timestamp found." )
            
        
        startElement( gen, tf, 'installer' )
        writeElement( gen, tf, 'sourceUrl', result._installerSourceLocation )
        writeElement( gen, tf, 'platform', result._installerTargetPlatform )
        #TODO revision
        endElement( gen, tf, 'installer' )

        if result._testcase != None:
            startElement( gen, tf, 'testCase' )
            writeElement( gen, tf, 'name', result._testcase.name() )

writeElement( gen, atom, 'title', result.constructTitle() )
        writeElement( gen, atom, 'updated', datetime.datetime.now().isoformat() )

        writeElement( gen, tf, 'errorSummary', exitStatusAsString( result.status() ) )

        writeElement( gen, tf, 'host', socket.gethostname() )
        if result._testStart != None:
            writeElement( gen, tf, 'testStart', result._testStart.isoformat() )
        else:
            result._internalErrors.append( "Result generator: no start timestamp found." )

        if result._testEnd != None:
            writeElement( gen, tf, 'testEnd', result._testEnd.isoformat() )
        else:
            result._internalErrors.append( "Result generator: no end timestamp found." )
            
        
        startElement( gen, tf, 'installer' )
        writeElement( gen, tf, 'sourceUrl', result._installerSourceLocation )
        writeElement( gen, tf, 'platform', result._installerTargetPlatform )
        #TODO revision
        endElement( gen, tf, 'installer' )

        if result._testcase != None:
            startElement( gen, tf, 'testCase' )
            writeElement( gen, tf, 'name', result._testcase.name() )
            writeElement( gen, tf, 'path', result._testcase.path() )
            writeElement( gen, tf, 'installScript', result._testcase.installscript() )
            endElement( gen, tf, 'testCase' )
        else:
            result._internalErrors.append( "Result generator: No test case given." )

if result._testcase != None:
            startElement( gen, tf, 'testCase' )
            writeElement( gen, tf, 'name', result._testcase.name() )
            writeElement( gen, tf, 'path', result._testcase.path() )
            writeElement( gen, tf, 'installScript', result._testcase.installscript() )
            endElement( gen, tf, 'testCase' )
        else:
            result._internalErrors.append( "Result generator: No test case given." )

        if result._installationResult != None:
            startElement( gen, tf, 'installationResult' )
            writeElement( gen, tf, 'exitCode', str( result._installationResult.exitCode ) )    
            writeElement( gen, tf, 'exitStatus', exitStatusAsString( result._installationResult.exitStatus ) )    
            endElement( gen, tf, 'installationResult' )
        else:
            result._internalErrors.append( "Result generator: No installation result given." )
        startElement( gen, tf, 'checkerResult' )
        
        for err in result._checkerErrors:
            writeElement( gen, tf, 'error', err )    
        endElement( gen, tf, 'checkerResult' )
            
        startElement( gen, tf, 'virtualMachine' )
        writeElement( gen, tf, 'path', result._vm.vmxPath() )
        writeElement( gen, tf, 'platform', result._vm.ostype() )
        writeElement( gen, tf, 'snapshot', result._vm.snapshot() )
        endElement( gen, tf, 'virtualMachine' )

        startElement( gen, tf, 'internalErrors' )
        for i in result._internalErrors:
            writeElement( gen, tf, 'internalError', str( i ) )

startElement( gen, tf, 'installer' )
        writeElement( gen, tf, 'sourceUrl', result._installerSourceLocation )
        writeElement( gen, tf, 'platform', result._installerTargetPlatform )
        #TODO revision
        endElement( gen, tf, 'installer' )

        if result._testcase != None:
            startElement( gen, tf, 'testCase' )
            writeElement( gen, tf, 'name', result._testcase.name() )
            writeElement( gen, tf, 'path', result._testcase.path() )
            writeElement( gen, tf, 'installScript', result._testcase.installscript() )
            endElement( gen, tf, 'testCase' )
        else:
            result._internalErrors.append( "Result generator: No test case given." )

        if result._installationResult != None:
            startElement( gen, tf, 'installationResult' )
            writeElement( gen, tf, 'exitCode', str( result._installationResult.exitCode ) )    
            writeElement( gen, tf, 'exitStatus', exitStatusAsString( result._installationResult.exitStatus ) )    
            endElement( gen, tf, 'installationResult' )
        else:
            result._internalErrors.append( "Result generator: No installation result given." )
        startElement( gen, tf, 'checkerResult' )
        
        for err in result._checkerErrors:
            writeElement( gen, tf, 'error', err )    
        endElement( gen, tf, 'checkerResult' )
            
        startElement( gen, tf, 'virtualMachine' )
        writeElement( gen, tf, 'path', result._vm.vmxPath() )