code: def merge_configurations(configurations):
      
      configuration = {}
      for c in configurations:
          for k, v in c.iteritems():
              if k in configuration:
                  raise ValueError('%s already in a previous base configuration' % k)
              configuration[k] = v
      return configuration
docs: Merge configurations together and raise error if a conflict is detected
  
      :param configurations: configurations to merge together
      :type configurations: list of :attr:`~pyextdirect.configuration.Base.configuration` dicts
      :return: merged configurations as a single one
      :rtype: dict