input: Write a python function to sort a list of tuples based on their float values.
  assert sort_by_float_value([('item1', '12.20'), ('item2', '15.10'), ('item3', '24.5')])==[('item3', '24.5'), ('item2', '15.10'), ('item1', '12.20')]
  assert sort_by_float_value([('item1', '15'), ('item2', '10'), ('item3', '20')])==[('item3', '20'), ('item1', '15'), ('item2', '10')]
  assert sort_by_float_value([('item1', '5'), ('item2', '10'), ('item3', '14')])==[('item3', '14'), ('item2', '10'), ('item1', '5')]
output: def sort_by_float_value(input_list):
      return sorted(input_list, key=lambda x: float(x[1]), reverse=True)