docs: def check_positive_integer(name, value):
      """Check a value is a positive integer.
  
      Returns the value if so, raises ValueError otherwise.
  
      """
      try:
          value = int(value)
          is_positive = (value > 0)
      except ValueError:
          raise ValueError('%s should be an integer; got %r' % (name, value))
  
      if is_positive:
          return value
      else:
          raise ValueError('%s should be positive; got %r' % (name, value))