class_docstr: Tests for CopyTo functions of Descriptor.
code: def testCopyToProto_SeveralExtensions(self):
      TEST_MESSAGE_WITH_SEVERAL_EXTENSIONS_ASCII = """
        name: 'TestMultipleExtensionRanges'
        extension_range: <
          start: 42
          end: 43
        >
        extension_range: <
          start: 4143
          end: 4244
        >
        extension_range: <
          start: 65536
          end: 536870912
        >
        """
  
      self._InternalTestCopyToProto(
          unittest_pb2.TestMultipleExtensionRanges.DESCRIPTOR,
          descriptor_pb2.DescriptorProto,
          TEST_MESSAGE_WITH_SEVERAL_EXTENSIONS_ASCII,
      )
  
imports: import unittest
  from google.protobuf import unittest_custom_options_pb2
  from google.protobuf import unittest_import_pb2
  from google.protobuf import unittest_pb2
  from google.protobuf import descriptor_pb2
  from google.protobuf import descriptor
  from google.protobuf import text_format
label_desc: Use image node_id 9 for calling the DescriptorCopyToProtoTest obj's underlying member method code with example usage: obj.testCopyToProto_SeveralExtensions() without return types