Given an array of diagnostic test timestamps, find the longest continuous block of time where no system errors were recorded.
Treat each value as the timestamp, in seconds, when an error was recorded. Return the largest elapsed time between any two consecutive error timestamps after sorting the input. Return 0 when fewer than two timestamps are provided.
Function: def longest_error_free_block(timestamps): Input: a list of integers. Output: an integer duration.
def longest_error_free_block(timestamps):