Update readme

Author: hardbyte

README.md

@@ -16,6 +16,7 @@ Basic usage:
 
 ```python
 from cel import evaluate
+
 expression = "age > 21"
 result = evaluate(expression, {"age": 18})
 print(result)  # False
@@ -34,10 +35,10 @@ evaluate(
         "claim": {"group": "hardbyte"}
     }
 )
+True
 ```
 ## Future work
 
-Support for converting Python datetime objects and timedeltas into CEL types.
 
 ### Command line interface
 

tests/test_basics.py

@@ -45,6 +45,10 @@ def test_timestamp_context_with_timezone():
     assert cel.evaluate("now", {'now': now}) == now
 
 
+def test_timestamp_add_duration():
+    now = datetime.datetime.now(datetime.timezone.utc)
+    cel.evaluate("start_time + duration('1h')", {'start_time': now}) == now + datetime.timedelta(hours=1)
+
 def test_timestamp_context_without_timezone():
     now = datetime.datetime.now()
     assert cel.evaluate("now", {'now': now})