Implement Safe Average Function

Write a Python function named average(values) that calculates and returns the arithmetic mean of a given list of numbers.

Requirements

• If the input list values is empty, the function must return 0.
• The input values will be a flat list containing only numeric types (integers or floats).
• The function must not modify (mutate) the original input list.

Examples

• average([1, 2, 3]) should return 2.0
• average([-1, 1]) should return 0.0
• average([]) should return 0