input: Write a python function to round a floating point number to a certain number of decimal places.
  assert round_float(2.71828, 3) == 2.718
  assert round_float(3.14159, 2) == 3.14
  assert round_float(1.23456, 4) == 1.2346
output: def round_float(number, decimals):
      return round(number, decimals)