docs: def report(self):
          """
          Performs rollups, prints report of sockets opened.
          """
          aggregations = dict(
              (test, Counter().rollup(values))
              for test, values in self.socket_warnings.items()
          )
          total = sum(
              len(warnings)
              for warnings in self.socket_warnings.values()
          )
  
          def format_test_statistics(test, counter):
              return "%s:\n%s" % (
                  test,
                  '\n'.join(
                      '  - %s: %s' % (socket, count)
                      for socket, count in counter.items()
                  )
              )
  
          def format_statistics(aggregations):
              return '\n'.join(
                  format_test_statistics(test, counter)
                  for test, counter in aggregations.items()
              )
  
          # Only print the report if there are actually things to report.
          if aggregations:
              print('=' * 70, file=self.stream)
              print(
                  'NON-WHITELISTED SOCKETS OPENED: %s' % total,
                  file=self.stream,
              )
              print('-' * 70, file=self.stream)
              print(format_statistics(aggregations), file=self.stream)