Symbolic doesn't works after loading

[maby200]

Hello, I am trying to use symbolic in octave.
First, downloaded and installed symbolic with:
         pkg install -forge symbolic
         pkg load symbolic
Then, started to write some code
         syms x
and next thing appeared:

Initializing communication with SymPy using a popen2() pipe.
"python" no se reconoce como un comando interno o externo,
programa o archivo por lotes ejecutable.
error: Cannot run the Python executable "python"
    Python and SymPy are needed for most Symbolic features.
    Is Python installed?  Is your "path" configured correctly?
error: called from
    assert_have_python_and_sympy at line 24 column 5
    python_ipc_popen2 at line 78 column 5
    python_ipc_driver at line 59 column 13
    python_cmd at line 164 column 9
    valid_sym_assumptions at line 38 column 10
    assumptions at line 82 column 7
    syms at line 97 column 13

I have Python 2.7 installed.
Is anything wrong with it?



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