chore: Update Cohere integration to use new generic callable (de)seri…

…alizers for their callback handlers (#453)

* (de)serialize callback properly

* lint

* check for None

integrations/cohere/src/haystack_integrations/components/generators/cohere/generator.py

@@ -2,10 +2,10 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 import logging
-import sys
 from typing import Any, Callable, Dict, List, Optional, cast
 
-from haystack import DeserializationError, component, default_from_dict, default_to_dict
+from haystack import component, default_from_dict, default_to_dict
+from haystack.components.generators.utils import deserialize_callback_handler, serialize_callback_handler
 from haystack.dataclasses import StreamingChunk
 from haystack.utils import Secret, deserialize_secrets_inplace
 
@@ -89,19 +89,10 @@ def to_dict(self) -> Dict[str, Any]:
         """
         Serialize this component to a dictionary.
         """
-        if self.streaming_callback:
-            module = self.streaming_callback.__module__
-            if module == "builtins":
-                callback_name = self.streaming_callback.__name__
-            else:
-                callback_name = f"{module}.{self.streaming_callback.__name__}"
-        else:
-            callback_name = None
-
         return default_to_dict(
             self,
             model=self.model,
-            streaming_callback=callback_name,
+            streaming_callback=serialize_callback_handler(self.streaming_callback) if self.streaming_callback else None,
             api_base_url=self.api_base_url,
             api_key=self.api_key.to_dict(),
             **self.model_parameters,
@@ -114,20 +105,10 @@ def from_dict(cls, data: Dict[str, Any]) -> "CohereGenerator":
         """
         init_params = data.get("init_parameters", {})
         deserialize_secrets_inplace(init_params, ["api_key"])
-        streaming_callback = None
         if "streaming_callback" in init_params and init_params["streaming_callback"] is not None:
-            parts = init_params["streaming_callback"].split(".")
-            module_name = ".".join(parts[:-1])
-            function_name = parts[-1]
-            module = sys.modules.get(module_name, None)
-            if not module:
-                msg = f"Could not locate the module of the streaming callback: {module_name}"
-                raise DeserializationError(msg)
-            streaming_callback = getattr(module, function_name, None)
-            if not streaming_callback:
-                msg = f"Could not locate the streaming callback: {function_name}"
-                raise DeserializationError(msg)
-            data["init_parameters"]["streaming_callback"] = streaming_callback
+            data["init_parameters"]["streaming_callback"] = deserialize_callback_handler(
+                init_params["streaming_callback"]
+            )
         return default_from_dict(cls, data)
 
     @component.output_types(replies=List[str], meta=List[Dict[str, Any]])