Explain the following Python function to someone with no programming experience: def binary_search(arr, target): low = 0; high = len(arr) - 1; while low <= high: mid = (low + high) // 2; if arr[mid] == target: return mid; elif arr[mid] < target: low = mid + 1; else: high = mid - 1; return -1. Use everyday analogies and break it down step by step.