`_dalle_image_url` returns list of urls if n>1 (#11800)

- **Description:** Updated the `_dalle_image_url` method to return a
list of URLs if self.n>1,
  - **Issue:** #10691,
  - **Dependencies:** unsure,
  - **Tag maintainer:** @eyurtsev,
  - **Twitter handle:** @silvhua
---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/langchain/langchain/utilities/dalle_image_generator.py

@@ -8,29 +8,25 @@ from langchain.utils import get_from_dict_or_env
 class DallEAPIWrapper(BaseModel):
     """Wrapper for OpenAI's DALL-E Image Generator.
 
-    Docs for using:
-    1. pip install openai
+    Usage instructions:
+    1. `pip install openai`
     2. save your OPENAI_API_KEY in an environment variable
-
     """
 
     client: Any  #: :meta private:
     openai_api_key: Optional[str] = None
-    """number of images to generate"""
     n: int = 1
-    """size of image to generate"""
+    """Number of images to generate"""
     size: str = "1024x1024"
+    """Size of image to generate"""
+    separator: str = "\n"
+    """Separator to use when multiple URLs are returned."""
 
     class Config:
         """Configuration for this pydantic object."""
 
         extra = Extra.forbid
 
-    def _dalle_image_url(self, prompt: str) -> str:
-        params = {"prompt": prompt, "n": self.n, "size": self.size}
-        response = self.client.create(**params)
-        return response["data"][0]["url"]
-
     @root_validator()
     def validate_environment(cls, values: Dict) -> Dict:
         """Validate that api key and python package exists in environment."""
@@ -42,19 +38,15 @@ class DallEAPIWrapper(BaseModel):
 
             openai.api_key = openai_api_key
             values["client"] = openai.Image
-        except ImportError:
-            raise ValueError(
+        except ImportError as e:
+            raise ImportError(
                 "Could not import openai python package. "
                 "Please it install it with `pip install openai`."
-            )
+            ) from e
         return values
 
     def run(self, query: str) -> str:
         """Run query through OpenAI and parse result."""
-        image_url = self._dalle_image_url(query)
-
-        if image_url is None or image_url == "":
-            # We don't want to return the assumption alone if answer is empty
-            return "No image was generated"
-        else:
-            return image_url
+        response = self.client.create(prompt=query, n=self.n, size=self.size)
+        image_urls = self.separator.join([item["url"] for item in response["data"]])
+        return image_urls if image_urls else "No image was generated"