code: func (c *EndpointConfig) mappedChannelName(networkConfig *fab.NetworkConfig, channelName string) string {
  
  	// if channelName is the original key found in the Channels map config, then return it as is
  	_, ok := networkConfig.Channels[strings.ToLower(channelName)]
  	if ok {
  		return channelName
  	}
  
  	// if !ok, then find a channelMatcher for channelName
  
  	//Return if no channelMatchers are configured
  	if len(c.channelMatchers) == 0 {
  		return defaultEntity
  	}
  
  	//loop over channelMatchers to find the matching channel name
  	for _, matcher := range c.channelMatchers {
  		if matcher.regex.MatchString(channelName) {
  			// get the matching matchConfig from the index number
  			return matcher.matchConfig.MappedName
  		}
  	}
  
  	return defaultEntity
  }
docs: // MappedChannelName will return channelName if it is an original channel name in the config
  // if it is not, then it will try to find a channelMatcher and return its MappedName.
  // If more than one matcher is found, then the first matcher in the list will be used.