Segmentation fault on help(entity) about python-dialogflow HOT 7 CLOSED

(venv366) > python                                                                                                                                                                      Python 3.6.6 (default, Oct 18 2018, 15:02:58)
[GCC 4.2.1 Compatible Apple LLVM 10.0.0 (clang-1000.10.44.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import dialogflow as df
>>> project_id = "test-project-test"
>>> entity_name = "test-entity-type"

>>> client = df.EntityTypesClient()
>>>
>>> entity_id = "blahblah-blah-blah-blahblah"
>>>
>>> name = client.entity_type_path(project_id, entity_id)
>>> entity = client.get_entity_type(name)
>>>
>>> help(entity)
[1]    4129 segmentation fault  python

import dialogflow
help(dialogflow.types.entity_type_pb2.EntityType)

(lldb) run test.py
Process 14821 launched: '/Users/crwilcox/scratch/google-cloud-dialogflow/venv366/bin/python' (x86_64)
Process 14821 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
    frame #0: 0x0000000104b66c69 _message.cpython-36m-darwin.so`google::protobuf::python::message_meta::GetExtensionsByName(google::protobuf::python::CMessageClass*, void*) + 41
_message.cpython-36m-darwin.so`google::protobuf::python::message_meta::GetExtensionsByName:
->  0x104b66c69 <+41>: movq   0x10(%rax), %rax
    0x104b66c6d <+45>: movq   0x360(%rdi), %rsi
    0x104b66c74 <+52>: leaq   -0x40(%rbp), %rdx
    0x104b66c78 <+56>: movq   %rax, %rdi
Target 0: (python) stopped.

pip freeze
cachetools==2.1.0
certifi==2018.10.15
chardet==3.0.4
dialogflow==0.5.1
google-api-core==1.5.0
google-auth==1.5.1
googleapis-common-protos==1.5.3
grpcio==1.16.0
idna==2.7
protobuf==3.6.1
pyasn1==0.4.4
pyasn1-modules==0.2.2
pytz==2018.6
requests==2.20.0
rsa==4.0
six==1.11.0
urllib3==1.24