code: def to_yaml(cls, config, compact=False, indent=2, level=0):
          
          lines = ""
          if isinstance(config, ConfigTree):
              if len(config) > 0:
                  if level > 0:
                      lines += '\n'
                  bet_lines = []
                  for key, item in config.items():
                      bet_lines.append('{indent}{key}: {value}'.format(
                          indent=''.rjust(level * indent, ' '),
                          key=key.strip('"'),  # for dotted keys enclosed with "" to not be interpreted as nested key,
                          value=cls.to_yaml(item, compact, indent, level + 1))
                      )
                  lines += '\n'.join(bet_lines)
          elif isinstance(config, list):
              config_list = [line for line in config if line is not None]
              if len(config_list) == 0:
                  lines += '[]'
              else:
                  lines += '\n'
                  bet_lines = []
                  for item in config_list:
                      bet_lines.append('{indent}- {value}'.format(indent=''.rjust(level * indent, ' '),
                                                                  value=cls.to_yaml(item, compact, indent, level + 1)))
                  lines += '\n'.join(bet_lines)
          elif isinstance(config, basestring):
              # if it contains a \n then it's multiline
              lines = config.split('\n')
              if len(lines) == 1:
                  lines = config
              else:
                  lines = '|\n' + '\n'.join([line.rjust(level * indent, ' ') for line in lines])
          elif config is None or isinstance(config, NoneValue):
              lines = 'null'
          elif config is True:
              lines = 'true'
          elif config is False:
              lines = 'false'
          else:
              lines = str(config)
          return lines
docs: Convert HOCON input into a YAML output
  
          :return: YAML string representation
          :type return: basestring