input: Write a python function to convert a decimal number to its binary representation.
  assert decimal_to_binary(5) == '101'
  assert decimal_to_binary(10) == '1010'
  assert decimal_to_binary(0) == '0'
  assert decimal_to_binary(16) == '10000'
  assert decimal_to_binary(1) == '1'
output: def decimal_to_binary(n):
      return bin(n)[2:]