input: Write a function to convert a given number into its binary representation. The function should return the binary string of the number. If the number is 0, it should return '0'.
  
  def convert_to_binary(num):
      # check if the number is 0, if so return '0'
      if num == 0:
          return '0'
      
      # initialize an empty binary string
      binary = ''
      
      # loop through the number and get the remainder 
      # which is the bits of the binary
      while num != 0:
          remainder = num % 2
          binary = str(remainder) + binary
          num = num // 2
      
      return binary
  
  # assert tests
  assert convert_to_binary(0) == '0'
  assert convert_to_binary(10) == '1010'
  assert convert_to_binary(7) == '111'
  assert convert_to_binary(255) == '11111111'
  assert convert_to_binary(1) == '1'
output: def convert_to_binary(num):
      if num == 0:
          return '0'
      
      binary = ''
      
      while num != 0:
          remainder = num % 2
          binary = str(remainder) + binary
          num = num // 2
      
      return binary