Powershell changes

install-python.ps1

@@ -11,31 +11,21 @@ function Cleanup {
     Stop-Process $PID
 }
 
-function Download-Python {
-    $arch ="$env:PROCESSOR_ARCHITECTURE"
-    $url = ""
-
-    switch($arch) {
-        "amd64" {
-            Write-Host "Downloading x64 version of Python."
-            $url = "https://www.python.org/ftp/python/3.7.3/python-3.7.3-amd64-webinstall.exe"
-        }
-        "x86" {
-            Write-Host "Downloading x86 version of Python."
-	        $url = "https://www.python.org/ftp/python/3.7.3/python-3.7.3-webinstall.exe"
-        }
-        default {
-            Write-Host "Unable to determine the Python download url for processor type: $arch."
-        }
-    }
-
-    if (-not ([string]::IsNullOrEmpty($url))) {
-        $client = New-Object System.Net.WebClient
-        $client.DownloadFile($url, $python)
-        return $True
+function Get-PythonInstallationTarget {
+    if ([Environment]::Is64BitOperatingSystem) {
+        Write-Host "Downloading x64 version of Python."
+        return "https://www.python.org/ftp/python/3.7.3/python-3.7.3-amd64-webinstall.exe"
+    } else {
+        Write-Host "Downloading x86 version of Python."
+        return "https://www.python.org/ftp/python/3.7.3/python-3.7.3-webinstall.exe"
     }
+}
 
-    return $False
+function Download-Python {
+    $url = Get-PythonInstallationTarget
+    $client = New-Object System.Net.WebClient
+    $client.DownloadFile($url, $PythonInstaller)
+    return $True
 }
 
 if (Assert-IsPythonRequired) {