feat: add type hints to event logger util

Summary:

Test Plan:

src/llama_stack_client/lib/agents/event_logger.py

@@ -4,15 +4,15 @@
 # This source code is licensed under the terms described in the LICENSE file in
 # the root directory of this source tree.
 
-from typing import Optional
+from typing import Any, Iterator, Optional, Tuple
 
 from termcolor import cprint
 
 from llama_stack_client.types import InterleavedContent, ToolResponseMessage
 
 
 def interleaved_content_as_str(content: InterleavedContent, sep: str = " ") -> str:
-    def _process(c) -> str:
+    def _process(c: Any) -> str:
         if isinstance(c, str):
             return c
         elif hasattr(c, "type"):
@@ -36,36 +36,38 @@ def __init__(
         self,
         role: Optional[str] = None,
         content: str = "",
-        end: str = "\n",
-        color="white",
-    ):
+        end: Optional[str] = "\n",
+        color: str = "white",
+    ) -> None:
         self.role = role
         self.content = content
         self.color = color
         self.end = "\n" if end is None else end
 
-    def __str__(self):
+    def __str__(self) -> str:
         if self.role is not None:
             return f"{self.role}> {self.content}"
         else:
             return f"{self.content}"
 
-    def print(self, flush=True):
+    def print(self, flush: bool = True) -> None:
         cprint(f"{str(self)}", color=self.color, end=self.end, flush=flush)
 
 
 class TurnStreamEventPrinter:
-    def __init__(self):
-        self.previous_event_type = None
-        self.previous_step_type = None
+    def __init__(self) -> None:
+        self.previous_event_type: Optional[str] = None
+        self.previous_step_type: Optional[str] = None
 
-    def yield_printable_events(self, chunk):
+    def yield_printable_events(self, chunk: Any) -> Iterator[TurnStreamPrintableEvent]:
         for printable_event in self._yield_printable_events(chunk, self.previous_event_type, self.previous_step_type):
             yield printable_event
 
         self.previous_event_type, self.previous_step_type = self._get_event_type_step_type(chunk)
 
-    def _yield_printable_events(self, chunk, previous_event_type=None, previous_step_type=None):
+    def _yield_printable_events(
+        self, chunk: Any, previous_event_type: Optional[str] = None, previous_step_type: Optional[str] = None
+    ) -> Iterator[TurnStreamPrintableEvent]:
         if hasattr(chunk, "error"):
             yield TurnStreamPrintableEvent(role=None, content=chunk.error["message"], color="red")
             return
@@ -151,7 +153,7 @@ def _yield_printable_events(self, chunk, previous_event_type=None, previous_step
                         color="green",
                     )
 
-    def _get_event_type_step_type(self, chunk):
+    def _get_event_type_step_type(self, chunk: Any) -> Tuple[Optional[str], Optional[str]]:
         if hasattr(chunk, "event"):
             previous_event_type = chunk.event.payload.event_type if hasattr(chunk, "event") else None
             previous_step_type = (
@@ -162,7 +164,7 @@ def _get_event_type_step_type(self, chunk):
 
 
 class EventLogger:
-    def log(self, event_generator):
+    def log(self, event_generator: Iterator[Any]) -> Iterator[TurnStreamPrintableEvent]:
         printer = TurnStreamEventPrinter()
         for chunk in event_generator:
             yield from printer.yield_printable_events(chunk)