cluster.py

def is_master(self):
  """Return true if there's only one master and we're it"""

  masters = [
    key
    for key in self.store.keys()
    if self.store[key]["master"]
  ]

  if len(masters) == 1 and masters[0] == self.hostname:
    return True
  else:
    return False

    def check_state(self):
        """return an iterable for the current cluster state."""
        return [self.state[x]["master"] for x in self.state.keys()]

    def is_master(self):
        """Return true if there's only one master and we're it"""
        # any(iter) short-circuits on first !True. Calling twice checks iter
        # for another True. Lastly, check our hostname had the True
        return self.check_state().count(True) == 1