[NvimError: String cannot contain newlines] #37

When I start debugging with :dbg, an error occurred. Following is the detail:
Error detected while processing function provider#python#Call:
line 18:
Traceback (most recent call last):

File "", line 1, in

File "/Users/ke/.local/share/nvim/plugged/vim-debug/vim_debug/commands.py", line 19, in debugger_cmd
return start(*shlex.split(plain))

File "/Users/ke/.local/share/nvim/plugged/vim-debug/vim_debug/commands.py", line 88, in start
debugger.start_py(fname)

File "/Users/ke/.local/share/nvim/plugged/vim-debug/vim_debug/new_debugger.py", line 114, in start_py
return self.start()

File "/Users/ke/.local/share/nvim/plugged/vim-debug/vim_debug/new_debugger.py", line 144, in start
self.ui.startup()

File "/Users/ke/.local/share/nvim/plugged/vim-debug/vim_debug/ui.py", line 47, in startup
self.create()

File "/Users/ke/.local/share/nvim/plugged/vim-debug/vim_debug/ui.py", line 84, in create
self.windows['output'].create('vertical belowright new')

File "/Users/ke/.local/share/nvim/plugged/vim-debug/vim_debug/window.py", line 53, in create
self.buffer[:] = [self.dtext]

File "/Users/ke/Library/Python/2.7/lib/python/site-packages/neovim/api/buffer.py", line 65, in setitem
return self.request('nvim_buf_set_lines', start, end, False, lines)

File "/Users/ke/Library/Python/2.7/lib/python/site-packages/neovim/api/common.py", line 44, in request
return self._session.request(name, self, *args, **kwargs)

File "/Users/ke/Library/Python/2.7/lib/python/site-packages/neovim/api/nvim.py", line 170, in request
res = self._session.request(name, *args, **kwargs)

File "/Users/ke/Library/Python/2.7/lib/python/site-packages/neovim/msgpack_rpc/session.py", line 100, in request
raise self.error_wrapper(err)

NvimError: String cannot contain newlines