"""Optimize prompt for Imagen API by removing Gemini-specific formatting and enhancing it with Imagen best practices.

This function processes a given prompt to make it suitable for the Imagen API. It removes Gemini-specific formatting, cleans up extra whitespace, and adds enhancements based on the content of the prompt. Additionally, it ensures the prompt does not exceed Imagen's token limit.

Args:
    prompt (str): The input prompt to be optimized for the Imagen API.

Returns:
    str: The optimized prompt, cleaned and enhanced according to Imagen best practices.

The function performs the following steps:
1. Removes Gemini-specific formatting such as 'Enhanced prompt:' and 'Aspect ratio:'.
2. Cleans up extra whitespace by joining the prompt into a single line.
3. Adds specific enhancements if the prompt contains keywords related to LinkedIn professional content or technology.
4. Ensures the prompt does not exceed Imagen's 480 token limit by truncating it if necessary.

Based on Imagen prompt guide: https://ai.google.dev/gemini-api/docs/imagen
"""
You should write code starting with:
def _optimize_prompt_for_imagen(prompt: str) -> str:
    pass

