(nums)
return missing
Returns the missing number from a sequence of unique integers
    in range [0..n] in O(n) time and space. The difference between
    consecutive integers cannot be more than 1. If the sequence is
    already complete, the next integer in the sequence will be returned.

    >>> find_missing_number(i for i in range(0, 10000) if i != 1234)
    1234
    >>> find_missing_number([4, 1, 3, 0, 6, 5, 2])
    7
Returns the missing number from a sequence of unique integers
    in range [0..n] in O(n) time and space. The difference between
    consecutive integers cannot be more than 1. If the sequence is
    already complete, the next integer in the sequence will be returned.
Returns the missing number from a sequence of unique integers in range [ 0 .. n ] in O ( n ) time and space . The difference between consecutive integers cannot be more than 1 . If the sequence is already complete the next integer in the sequence will be returned .
def find_missing_number(nums):
    """Returns the missing number from a sequence of unique integers
    in range [0..n] in O(n) time and space. The difference between
    consecutive integers cannot be more than 1. If the sequence is
    already complete, the next integer in the sequence will be returned.

    >>> find_missing_number(i for i in range(0, 10000) if i != 1234)
    1234
    >>> find_missing_number([4, 1, 3, 0, 6, 5, 2])
    7
    """

    missing = 0
    for i, num in enumerate(nums):
        missing ^= num
        missing ^= i + 1

    return missing
def find_missing_number ( nums ) : missing = 0 for i , num in enumerate ( nums ) : missing ^= num missing ^= i + 1 return missing