Add optional date param

src/main.py

@@ -1,5 +1,6 @@
-from fastapi import FastAPI
-import datetime
+from fastapi import FastAPI, HTTPException
+from datetime import datetime, date
+import dateutil.parser
 
 app = FastAPI()
 
@@ -21,11 +22,20 @@ ben_franklin_virtues = {
 
 
 @app.get("/")
-async def virtue():
+async def virtue(day: str = None):
     """
     Get the virtue of the week
     """
-    current_week = datetime.date.today().isocalendar()[1]
+    if day is None:
+        current_date = date.today()
+    else:
+        try:
+            current_date = dateutil.parser.parse(day).date()
+        except:
+            raise HTTPException(status_code=400, 
+                                detail="Invalid date format, please provide a date in the month/day/year format.")
+
+    current_week = current_date.isocalendar()[1]
 
     virtues = list(ben_franklin_virtues.keys())