def _execute_api_call(self, url):
    """Executes an API call to the given URL.

    Args:
        url (str): The URL to call.

    Returns:
        requests.Response: The response object from the API call.

    Raises:
        PermissionError: If there are credential issues.
        ValueError: If there's a request error.
        Exception: For any other unexpected errors.
    """
    try:
      headers = {
          "Content-Type": "application/json",
          "Authorization": f"Bearer {self._get_access_token()}",
      }

      response = requests.get(url, headers=headers)
      response.raise_for_status()
      return response

    except google.auth.exceptions.DefaultCredentialsError as e:
      raise PermissionError(f"Credentials error: {e}") from e

    except requests.exceptions.RequestException as e:
      if (
          "404" in str(e)
          or "Not found" in str(e)
          or "400" in str(e)
          or "Bad request" in str(e)
      ):
        raise ValueError(
            "Invalid request. Please check the provided"
            f" values of project({self.project}), location({self.location}),"
            f" connection({self.connection})."
        ) from e
      raise ValueError(f"Request error: {e}") from e

    except Exception as e:
      raise Exception(f"An unexpected error occurred: {e}") from e
Executes an API call to the given URL.

    Args:
        url (str): The URL to call.

    Returns:
        requests.Response: The response object from the API call.

    Raises:
        PermissionError: If there are credential issues.
        ValueError: If there's a request error.
        Exception: For any other unexpected errors.
    
src/google/adk/tools/application_integration_tool/clients/connections_client.py