<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Insert two new elements at the beginning of a list.
["a", "b", "c", "d"]<|im_end|>
<|im_start|>assistant
["x", "y", "a", "b", "c", "d"]<|im_end|>
