Build Error darkflow on 20.04 Ubuntu

[hiteshkumar1712]

the build works well on 18.04. But not on Ubuntu 20.04. Please help

/home/metro/anaconda3/envs/synvids1/include/python3.6m/unicodeobject.h:508:44: warning: signed and unsigned type in conditional expression [-Wsign-compare]
             ((const Py_UCS1 *)(data))[(index)] : \
                                                ^
    darkflow/cython_utils/nms.c:464:43: note: in expansion of macro ‘PyUnicode_READ’
       #define __Pyx_PyUnicode_READ(k, d, i)   PyUnicode_READ(k, d, i)
                                               ^~~~~~~~~~~~~~
    darkflow/cython_utils/nms.c:20082:53: note: in expansion of macro ‘__Pyx_PyUnicode_READ’
             if (__Pyx_PyUnicode_READ(kind, data1, 0) != __Pyx_PyUnicode_READ(kind, data2, 0)) {
                                                         ^~~~~~~~~~~~~~~~~~~~
    error: command 'gcc' failed with exit status 1
    ----------------------------------------
ERROR: Command errored out with exit status 1: /home/metro/anaconda3/envs/synvids1/bin/python -u -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-req-build-hfn_2i3c/setup.py'"'"'; __file__='"'"'/tmp/pip-req-build-hfn_2i3c/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-abjyialq/install-record.txt --single-version-externally-managed --compile --install-headers /home/metro/anaconda3/envs/synvids1/include/python3.6m/darkflow Check the logs for full command output.