Inbuilt function in *.ps1 is not recognizing

Question

I have written the code below, CreateLogFile is a function and it will be called at the beginning of the script file.

Saved the file in desktop as TestPS.ps1.

# Create a log file in the specified location.
CreateLogFile

#Create log file in the specified location and
#also change the name of existing log file.
Function CreateLogFile {
    If ((Test-Path D:\PSLogs\PSLog.log)) {
        $Date = Get-Date -UFormat '%Y%m%d%H%M%S'
        $FileName = "PSLogs_" + $Date
        #Write-Host $FileName
        Get-ChildItem D:\PSLogs\PSLog.log |
            Rename-Item -NewName {$_.name -replace '^PSLog', $FileName}
    }
    New-Item -Path D:\PSLogs\PSLog.log -ItemType File -Force
}

When I run the TestPS.ps1 file in PowerShell it is throwing the bellow error