Octave 4.2.2 and sympy 1.6

Iam trying to use Octave 4.2.2 with Symbolic pkg v.2.9.0 but I get this error related to sympy package:

Your kit looks good for running the Symbolic package.  Happy hacking!

>>
>> syms
Symbolic variables in current scope:
>> a = sym( "a" );
Symbolic pkg v2.9.0: /home/usuario/.local/lib/python3.6/site-packages/sympy/__init__.py:676: SymPyDeprecationWarning:

importing sympy.core.compatibility with 'from sympy import *' has been
deprecated since SymPy 1.6. Use import sympy.core.compatibility
instead. See https://github.com/sympy/sympy/issues/18245 for more
info.

  deprecated_since_version="1.6").warn()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 12, in octoutput_drv
  File "<stdin>", line 54, in octoutput
  File "<stdin>", line 55, in octoutput
  File "/home/usuario/.local/lib/python3.6/site-packages/sympy/__init__.py", line 677, in __getattr__
    return getattr(self.mod, name)
AttributeError: module 'sympy.core.compatibility' has no attribute 'integer_types'
Waiting................warning: readblock: timeout of 30 exceeded, breaking out
warning: called from
    readblock at line 101 column 7
    python_ipc_popen2 at line 99 column 14
    python_ipc_driver at line 62 column 13
    pycall_sympy__ at line 163 column 9
    sym at line 452 column 9
no output so far

error: ipc_popen2: something wrong? timed out starting python
error: called from
    python_ipc_popen2 at line 101 column 7
    python_ipc_driver at line 62 column 13
    pycall_sympy__ at line 163 column 9
    sym at line 452 column 9
>> a
error: 'a' undefined near line 1 column 1
>>

I dig into code and find this two references:

https://github.com/sympy/sympy/pull/18245 https://github.com/sympy/sympy/pull/19316

But Iam not a programmer so any idea is greatly appreciated.

I tried to uninstall sympy-1.6 and install sympy-1.5 but that doesn't work.

Thanks for your time.

Daniel