code: def with_unit(number, unit=None):
      
      if isinstance(number, tuple):
          number, unit = number
      if number == 0:
          return '0'
      if unit:
          number = str(number)
          if number.startswith('.'):
              number = '0' + number
          return "%s%s" % (number, unit)
      return number if isinstance(number, string_types) else str(number)
docs: Return number with unit
      args:
          number (mixed): Number
          unit (str): Unit
      returns:
          str