diff --git a/CHANGELOG.md b/CHANGELOG.md
index 71948fc..6e084d6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Formatting in all files with VSCode formatting according to the 'settings.json' file taken from Sampler
 - Added yaml format config settings 'singleQuote' and 'bracketSpacing' and reformatted all yaml files according to the new settings.
 - Cleanup
+  - Get-DatumType.ps1
   - Merge-DatumArray.ps1
   - Merge-Hashtable.ps1
   - Compare-Hashtable.ps1
diff --git a/source/Private/Get-DatumType.ps1 b/source/Private/Get-DatumType.ps1
index 629a5c0..91b5a89 100644
--- a/source/Private/Get-DatumType.ps1
+++ b/source/Private/Get-DatumType.ps1
@@ -1,6 +1,9 @@
 function Get-DatumType
 {
+    [OutputType([string])]
     param (
+        [Parameter(Mandatory = $true)]
+        [AllowNull()]
         [object]
         $DatumObject
     )
@@ -11,7 +14,7 @@ function Get-DatumType
     }
     elseif ($DatumObject -isnot [string] -and $DatumObject -is [System.Collections.IEnumerable])
     {
-        if ($Datumobject -as [hashtable[]])
+        if ($DatumObject -as [hashtable[]])
         {
             'hash_array'
         }