How might we make this Python Merge Sort implementation more Pythonic?
If you have any expression like the one below

if(x == 0) 


then you can rewrite it as

if not x


You can get rid of parenthesis and can make it more pythonic by writing like this.

Similarly you an rewrite :

if(len(leftSortedSeq) == 0):
    return rightSortedSeq
elif(len(rightSortedSeq) == 0):
    return leftSortedSeq


as

if not len(leftSortedSeq):
    return rightSortedSeq
elif not len(rightSortedSeq):
    return leftSortedSeq


If I were you I would avoid using excetions for the cases which can be avoided using simple if else. This will give the code more clarity.

We can avoid the exception by changing the code a bit.

I have also avoided conversion to tuple. The concatenation of tuple and list may cause problems. So its better to avoid unnecessary conversions.

lenLeftSeq = len(leftSortedSeq)
lenRightSeq = len(rightSortedSeq)

while leftPointer &lt; lenLeftSeq and rightPointer &lt; lenRightSeq:

    smallestInLeft = leftSortedSeq[leftPointer]
    smallestInRight = rightSortedSeq[rightPointer]

    if(smallestInLeft &lt; smallestInRight):
        mergedSeq.append(smallestInLeft)
        leftPointer += 1
    else:
        mergedSeq.append(smallestInRight)
        rightPointer += 1

return mergedSeq +
             leftSortedSeq[leftPointer:] +
             rightSortedSeq[rightPointer:]