Merge sort in python

mergesort.py

class MergeSort(object):
  
  @staticmethod
  def sort(array):
    if len(array) <= 1:
      return array    
    else:
      middle = len(array)/2
      left_half = MergeSort.sort(array[:middle])
      right_half =  MergeSort.sort(array[middle:])
      merged = []
      i,j,= 0,0
      while (i + j) < (len(left_half) + len(right_half)): 
        if i < len(left_half) and j < len(right_half):
          if left_half[i] < right_half[j]:
            merged.append(left_half[i])
            i += 1
          else:
            merged.append(right_half[j])
            j += 1       
        elif i < len(left_half):
          merged.append(left_half[i])
          i += 1
        elif j < len(right_half):
          merged.append(right_half[j])
          j += 1

      return merged