verify the size of the two matrices to ensure they are the same as required by matrix addition create new sparsematrix object with the same number of rows and columns as the other two duplicate the elements of the self matrix and store them in the new matrix iterate over the element list of the righthand side matrix (rhsmatrixto add the non-zero values to the corresponding elements in the new matrix the implementation of the add operation is provided in listing the first two steps of the add operation are straightforward the third step of copying the elements of the self matrix to the new matrix requires list duplicationwhich is handled by the first loop the second loop handles the fourth step outlined above by iterating over the list of matrixelement objects in the rhsmatrix and adding their values to the corresponding values in the new sparse matrix note the use of the getitem and setitem methods in the second loop this is necessary since the two methods properly manage any zero elements that may currently exist in the newmatrix or that may result after adding corresponding elements listing implementation of the sparsematrix add operation class sparsematrix def __add__selfrhsmatrix )assert rhsmatrix numrows(=self numrows(and rhsmatrix numcols(=self numcols()"matrix sizes not compatible for the add operation create the new matrix newmatrix sparsematrixself numrows()self numcols(duplicate the lhs matrix the elements are mutablethus we must create new objects and not simply copy the references for element in self _elementlist dupelement _matrixelement(element rowelement colelement valuenewmatrix _elementlist appenddupelement iterate through each non-zero element of the rhsmatrix for element in rhsmatrix _elementlist get the value of the corresponding element in the new matrix value newmatrixelement rowelement col value +element value store the new value back to the new matrix newmatrixelement rowelement col value return the new matrix return newmatrix