code: def normalize(value, unit):
      
      if value < 0:
          raise ValueError('Negative value: %s %s.' % (value, unit))
  
      if unit in functions.get_keys(INFORMATION_UNITS):
          return _normalize_information(value, unit)
      elif unit in TIME_UNITS:
          return _normalize_time(value, unit)
      else:
          # Unknown unit, just return it
          return functions.format_value(value), unit
docs: Converts the value so that it belongs to some expected range.
  
      Returns the new value and new unit.
  
      E.g:
  
      >>> normalize(1024, 'KB')
      (1, 'MB')
      >>> normalize(90, 'min')
      (1.5, 'hr')
      >>> normalize(1.0, 'object')
      (1, 'object')