combine_grid: Python exercise

Your mission

Implement combine_grid, which returns the grid of results of op applied to every value of left with every value of right.

left and right hold zero or more int values of any sign. op is always one of '+', '-' and '*'.
Return a list of rows: one row per value of left, in the same order, and in each row one cell per value of right, in the same order.
The cell in row i, column j is left[i] op right[j], with left[i] on the left of the operator.
An empty left gives []. An empty right gives one empty row per value of left.
Each call returns a new grid whose rows are lists of their own: changing one row never changes another row, nor the result of another call.

Implement combine_grid, which returns the grid of results of op applied to every value of left with every value of right.

left and right hold zero or more int values of any sign. op is always one of '+', '-' and '*'.
Return a list of rows: one row per value of left, in the same order, and in each row one cell per value of right, in the same order.
The cell in row i, column j is left[i] op right[j], with left[i] on the left of the operator.
An empty left gives []. An empty right gives one empty row per value of left.
Each call returns a new grid whose rows are lists of their own: changing one row never changes another row, nor the result of another call.

Implement combine_grid, which returns the grid of results of op applied to every value of left with every value of right.

left and right hold zero or more int values of any sign. op is always one of '+', '-' and '*'.
Return a list of rows: one row per value of left, in the same order, and in each row one cell per value of right, in the same order.
The cell in row i, column j is left[i] op right[j], with left[i] on the left of the operator.
An empty left gives []. An empty right gives one empty row per value of left.
Each call returns a new grid whose rows are lists of their own: changing one row never changes another row, nor the result of another call.

Implement combine_grid, which returns the grid of results of op applied to every value of left with every value of right.

left and right hold zero or more int values of any sign. op is always one of '+', '-' and '*'.
Return a list of rows: one row per value of left, in the same order, and in each row one cell per value of right, in the same order.
The cell in row i, column j is left[i] op right[j], with left[i] on the left of the operator.
An empty left gives []. An empty right gives one empty row per value of left.
Each call returns a new grid whose rows are lists of their own: changing one row never changes another row, nor the result of another call.