问题描述:
Write a function to extract the ranges that are missing from the given list with the given start range and end range values.

测试用例:
['assert extract_missing([(6, 9), (15, 34), (48, 70)], 2, 100) == [(2, 6), (9, 100), (9, 15), (34, 100), (34, 48), (70, 100)]', 'assert extract_missing([(7, 2), (15, 19), (38, 50)], 5, 60) == [(5, 7), (2, 60), (2, 15), (19, 60), (19, 38), (50, 60)]', 'assert extract_missing([(7, 2), (15, 19), (38, 50)], 1, 52) == [(1, 7), (2, 52), (2, 15), (19, 52), (19, 38), (50, 52)]']

生成的代码:
def extract_missing(ranges, start, end):
    missing_ranges = []
    
    # Start with the initial range from 'start' to the first range's start
    current_start = start
    
    for r in ranges:
        current_range_start, current_range_end = r
        
        # Add the missing range if there's a gap
        if current_start < current_range_start:
            missing_ranges.append((current_start, current_range_start))
        
        # Update the current start to be after the current range
        current_start = max(current_start, current_range_end)
    
    # Finally, add the range from the last range's end to 'end'
    if current_start < end:
        missing_ranges.append((current_start, end))
    
    return missing_ranges

# Test cases
assert extract_missing([(6, 9), (15, 34), (48, 70)], 2, 100) == [(2, 6), (9, 100), (9, 15), (34, 100), (34, 48), (70, 100)]
assert extract_missing([(7, 2), (15, 19), (38, 50)], 5, 60) == [(5, 7), (2, 60), (2, 15), (19, 60), (19, 38), (50, 60)]
assert extract_missing([(7, 2), (15, 19), (38, 50)], 1, 52) == [(1, 7), (2, 52), (2, 15), (19, 52), (19, 38), (50, 52)]