code: def good_coords(coords):
          
          if (len(coords) != 4):
              return False
          for coord in coords[0:3]:
              try:
                  num = float(coord)
                  if (math.isnan(num)):
                      return False
                  if (math.isinf(num)):
                      return False
              except ValueError:
                  return False
          return True
docs: passed a string array