make sure full mypy run in all python versions

.github/workflows/python_checks.yml

@@ -99,12 +99,14 @@ on:
             These are run in --disallow-untyped-defs mode
           required: false
           type: string
+          default: ''
       mypy-packages:
           description: >
             The names of Python packages to run simple mypy on.
             These are run in without --disallow-untyped-defs
           required: false
           type: string
+          default: ''
       rat_config_file:
         description: >
           Which xml config file to use for rat.
@@ -187,6 +189,7 @@ jobs:
         language: en_GB
 
     - name: Lint with mypy
+      if: ${{ inputs.mypy-packages != ''}}
       run: mypy --python-version ${{ matrix.python-version }} ${{ inputs.mypy-packages }}
 
     - name: Lint with mypy using disallow-untyped-def
@@ -259,7 +262,11 @@ jobs:
 
     - name: Lint with mypy
       if: ${{ (matrix.python-version != env.PRERELEASE || inputs.check_prereleases == 'true') && inputs.mypy-packages != '' }}
-      run: mypy ${{ inputs.mypy-packages }}
+      run: mypy --python-version ${{ matrix.python-version }} ${{ inputs.mypy-packages }}
+
+    - name: Lint with mypy using disallow-untyped-def
+      if: ${{ (matrix.python-version != env.PRERELEASE || inputs.check_prereleases == 'true') && inputs.mypy-full-packages != '' }}
+      run: mypy --python-version ${{ matrix.python-version }} --disallow-untyped-defs ${{ inputs.mypy-full-packages }}
 
     - name: Test with pytest
       if: ${{ (matrix.python-version != env.PRERELEASE || inputs.check_prereleases == 'true') &&  inputs.test_directories != ''}}