code: function findCallbacks (subscriptions, channel) {
      // First try to see if a callback for the exact channel exists
      if(Object.keys(subscriptions).indexOf(channel)!==-1)
          return subscriptions[channel];
      // If it doesn't then let's try to see if the channel matches a wildcard callback
      var pattern = matchesWildcard(subscriptions, channel);
      if (pattern!== undefined) {
          return subscriptions[pattern];
      }
      // If there's no exact match or wildcard we have to return undefined
      return undefined;
  }
docs: Helper function that selects the right callback when a message is received