class_docstr: Provides common methods for a protocol buffer object.
  
  Wraps a single string value. This makes testing equality easy.
code: def __eq__(self, other):
      return (
          isinstance(other, MockStringProto)
          and self.string == other.string
      )
  
file_path: magenta/magenta/common/testing_lib.py
imports: import numpy
  import six
  from google.protobuf import text_format
label_desc: Use image node_id 4 for calling the MockStringProto obj's underlying member method code with example usage: obj.__eq__(other) and returns: unknown