Use date for timebounds

src/analytics_query_analyzer/timebounds_analyzer.py

@@ -29,9 +29,7 @@ def __init__(
         self.current_date_provider = current_date_provider or date.today
 
     def analyze(self, expression: exp.Expression) -> list[TimeboundsRow]:
-        return _flatten_timebounds(
-            _stringify_results(self._analyze_internal(expression))
-        )
+        return _flatten_timebounds(self._analyze_internal(expression))
 
     def _analyze_internal(self, expression: exp.Expression) -> TimeboundsResults:
         if isinstance(expression, exp.Union):
@@ -631,20 +629,8 @@ def _normalize_iso_date(value: str) -> date | None:
         return None
 
 
-def _stringify_results(
-    results: TimeboundsResults,
-) -> dict[str, dict[str, str | None]]:
-    output: dict[str, dict[str, str | None]] = {}
-    for key, bounds in results.items():
-        output[key] = {
-            "lower": bounds["lower"].isoformat() if bounds["lower"] else None,
-            "upper": bounds["upper"].isoformat() if bounds["upper"] else None,
-        }
-    return output
-
-
 def _flatten_timebounds(
-    results: dict[str, dict[str, str | None]],
+    results: TimeboundsResults,
 ) -> list[TimeboundsRow]:
     rows: list[TimeboundsRow] = []
     for full_path, bounds in results.items():

src/analytics_query_analyzer/types.py

@@ -1,3 +1,4 @@
+from datetime import date
 from typing import TypedDict
 
 
@@ -9,5 +10,5 @@ class ReferenceRow(TypedDict):
 
 
 class TimeboundsRow(ReferenceRow):
-    lower: str | None
-    upper: str | None
+    lower: date | None
+    upper: date | None