当我尝试在Octave中使用symbolic包时，收到错误消息。
>> pkg load symbolic
>> syms x y
Traceback (most recent call last):
File "<string>", line 1, in <module>
ImportError: No module named sympy
OctSymPy v2.6.0: this is free software without warranty, see source.
Initializing communication with SymPy using a popen2() pipe.
error: Python cannot import SymPy: have you installed SymPy?
error: called from
assert_have_python_and_sympy at line 37 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
我做错了什么？