Create a function that returns the CSV representation of a two-dimensional numeric array. Example: input: [[ 0, 1, 2, 3, 4 ], [ 10,11,12,13,14 ], [ 20,21,22,23,24 ], [ 30,31,32,33,34 ]] output: '0,1,2,3,4\n' +'10,11,12,13,14\n' +'20,21,22,23,24\n' +'30,31,32,33,34' Array's length > 2.

def to_csv_string(array):
  return '\n'.join([','.join([str(j) for j in i]) for i in array])

to_csv_string([[ 0, 1, 2, 3, 4 ],
               [ 10,11,12,13,14 ],
               [ 20,21,22,23,24 ],
               [ 30,31,32,33,34 ]])