Class definition

The class definition for the Python semaphore object looks like this:

class _Semaphore(_Verbose):
  # After Tim Peters' semaphore class, but not quite the same (no maximum)
  def __init__(self, value=1, verbose=None):
      if value < 0:
          raise ValueError("semaphore initial value must be >= 0")
      _Verbose.__init__(self, verbose)
      self.__cond = Condition(Lock())
      self.__value = value

In the preceding constructor function of the semaphore class, you'll notice it takes in a value, which, unless otherwise set, defaults to 1.

In the class definition, the comments define a semaphore as follows: