code: def get_all_regions(self, region_names=None, filters=None):
          
          params = {}
          if region_names:
              self.build_list_params(params, region_names, 'RegionName')
          if filters:
              self.build_filter_params(params, filters)
          regions =  self.get_list('DescribeRegions', params,
                                   [('item', RegionInfo)], verb='POST')
          for region in regions:
              region.connection_cls = EC2Connection
          return regions
docs: Get all available regions for the EC2 service.
  
          :type region_names: list of str
          :param region_names: Names of regions to limit output
  
          :type filters: dict
          :param filters: Optional filters that can be used to limit
                          the results returned.  Filters are provided
                          in the form of a dictionary consisting of
                          filter names as the key and filter values
                          as the value.  The set of allowable filter
                          names/values is dependent on the request
                          being performed.  Check the EC2 API guide
                          for details.
  
          :rtype: list
          :return: A list of :class:`boto.ec2.regioninfo.RegionInfo`