Fixes TypeError from type hint incompatible to older Python

.github/workflows/pythonapp.yml

@@ -11,14 +11,20 @@ jobs:
 
     runs-on: ubuntu-latest
 
+    strategy:
+      matrix:
+        python-version: [ "3.9", "3.10", "3.11" ]
+        os: [ ubuntu-latest ]
+
     steps:
       - name: Install xclip
         run: sudo apt-get install -y xclip
       - uses: actions/checkout@v3
-      - name: Set up Python 3.11
+      - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:
-          python-version: 3.11
+          python-version: ${{ matrix.python-version }}
+          architecture: x64
 
       - name: Install dependencies
         run: |

src/dsr_shelx/dbfile.py

@@ -179,7 +179,7 @@ def __init__(self, maindb_path: str = '', userdb_path: str = ''):
         if userdb_path:
             self.parse(userdb_path, 'dsr_user_db')
 
-    def parse(self, dbpath: str = '', dbname: str = 'dsr_db') -> dict[str, dict[str, str]]:
+    def parse(self, dbpath: str = '', dbname: str = 'dsr_db') -> Dict[str, Dict[str, str]]:
         """
         This method returns all fragment name tags in the database
 
@@ -207,7 +207,7 @@ def parse(self, dbpath: str = '', dbname: str = 'dsr_db') -> dict[str, dict[str,
         []
         """
         frag_tag = ''
-        db: dict[str, dict[str, str]] = dict()
+        db: Dict[str, Dict[str, str]] = dict()
         start_regex = re.compile(r'<[^/].*>', re.IGNORECASE)  # regular expression for db tag.
         starttag = False
         fraglines = []