proto2cpp.py could not be found.

[peter18456]

1. Generate Doxygen configuration file with command 'doxygen -g '

e.g. doxygen -g doxyfile

2. In the Doxygen configuration file, find JAVADOC_AUTOBRIEF and set it enabled

JAVADOC_AUTOBRIEF = YES

3. In the Doxygen configuration file, find FILE_PATTERNS and add *.proto

FILE_PATTERNS = *.proto

4. In the Doxygen configuration file, find EXTENSION_MAPPING and add proto=C

EXTENSION_MAPPING = proto=C

5. In the Doxygen configuration file, find INPUT_FILTER and add this script

INPUT_FILTER = "python proto2cpp.py"

6. Run Doxygen with the modified configuration

doxygen doxyfile

after 6 steps, still warning:proto2cpp.py could not be found.
how to fix it?