UnboundLocalError: local variable 'pitch' referenced before assignment

[Summerxu86]

Hi, when I run preprocessor.py, I have this problem:
/preprocessor.py", line 92, in build_from_path
if len(pitch) > 0:
UnboundLocalError: local variable 'pitch' referenced before assignment
When I try to add a global declaration to the function, it shows
NameError: name 'pitch' is not defined
How should this be resolved? I would be grateful if I could get your guidance soon.