Merge Sort in Python

merge_sort.py

class Sorter:
    def __init__(self,data):
        self.data = data

    def do_msort(self):
        print("Original data",self.data)
        self.run_msort(0,len(self.data)-1)
        print("Sorted data  ",self.data)

    def run_msort(self,i,j):

        if j-i==0:
            return

        m = int((i+j)/2)
        self.run_msort(i,m)
        self.run_msort(m+1,j)

        tmp = []
        p=i
        q=m+1
        while p<=m or q<=j:
            if p<=m and q<=j:
                if self.data[p] < self.data[q]:
                    tmp.append(self.data[p])
                    p+=1
                else:
                    tmp.append(self.data[q])
                    q+=1
            else:
                if p<=m:
                    tmp.append(self.data[p])
                    p+=1
                else:
                    tmp.append(self.data[q])
                    q+=1

        self.data[i:j+1] = tmp 

Sorter([5,3,1,0,2,4,9,7,8,6]).do_msort()
Sorter([9,8,7,6,5,4,3,2,1,0]).do_msort()
Sorter([2,2,2,2,1,1,1,1,0,0]).do_msort()

$ python merge_sort.py
Original data [5, 3, 1, 0, 2, 4, 9, 7, 8, 6]
Sorted data   [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
Original data [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
Sorted data   [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
Original data [2, 2, 2, 2, 1, 1, 1, 1, 0, 0]
Sorted data   [0, 0, 1, 1, 1, 1, 2, 2, 2, 2]