Get element index closest to target element in a list of tuples

closest.py

# Modified from solution for numbers here: https://stackoverflow.com/a/12141511/8170714

# Tuple comparison solution from here: https://stackoverflow.com/a/31779268/8170714

def take_closest(self, list, element, idx=0):
        """
        Assumes myList is sorted. Returns closest value to element (tuple). 
        
        When comparing not all elements in tuple, set all other locations in tuple to nothing (e.g. (X,Y,)).
        
        idx: index (or slice) for the comparing target elements

        If two elements are equally close, return the smaller element.
        """
        pos = bisect_left(list, element)
        if pos == len(list):
            return pos-1
        before = list[pos - 1]
        after = list[pos]
        if after[idx] - element[idx] < element[idx] - before[idx]:
            return pos # after's idx
        else:
            return pos - 1 # before's idx