projects(imports): fix style py312 warning for xml root check

Signed-off-by: David Wallace <david.wallace@tu-darmstadt.de>

Author: MyPyDavid

rdmo/projects/imports.py

@@ -92,13 +92,15 @@ class RDMOXMLImport(Import):
         'application/xml': ['.xml']
     }
 
-    def check(self):
+    def check(self) -> bool:
         file_type, encoding = mimetypes.guess_type(self.file_name)
-        if file_type == 'application/xml' or file_type == 'text/xml':
+        if file_type in ('application/xml', 'text/xml'):
             self.root = read_xml_file(self.file_name)
-            if self.root and self.root.tag == 'project':
+            if self.root is not None and self.root.tag == 'project':
                 self.ns_map = get_ns_map(self.root)
                 return True
+        return False
+
 
     def process(self):
         if self.current_project is None: