Fix MatchParser matching extra unnecessary constructors

tetras_extraction/macao_12/script/extract_page.py

@@ -326,7 +326,7 @@ class MatchParser(JSParser):
     """A parser for the JS portion of an activity, that uses Python match statements
     to navigate the abstract syntax tree (AST) produced by Esprima"""
 
-    activity: Activity
+    activity: Optional[Activity] = None
 
     def __init__(self, graph: Graph, act_id: str) -> None:
         self.graph = graph
@@ -338,9 +338,15 @@ class MatchParser(JSParser):
         # Try to match our template with one of the top-level statements
         for statement in jstree.body:
             self.match_function(statement.toDict())
+
+        if self.activity is not None:
             return self.activity
+        else:
+            raise ParseError("No activity constructor found")
 
     def match_constructor_call(self, new_expr: dict):
+        if self.activity is not None:  # Ignore anything after the first match
+            return
         match new_expr:
             case {
                 "type": "NewExpression",