/usr/bin/env: 'python': No such file or directory

while giving following command

$ ./testall.sh 

it shows following error. Please give resolution.

$ ./testall.sh
Logfile: /tmp/testlib.197608/speedup_logs/2017-04-02T08:27:39.308841100

===========================>
Entering ./annotate_mwe
===========================>

1: Annotate candidates with NgramMatch detection
/mwetoolkit/bin/annotate_mwe.py -v  --to=TaggedPlainCorpus -c /mwetoolkit/test/annotate_mwe/local-input/NgramMatch/candidates.xml /mwetoolkit/test/annotate_mwe/local-input/NgramMatch/corpus.xml >/mwetoolkit/test/annotate_mwe/output/NgramMatch.txt
/usr/bin/env: 'python': No such file or directory
==============================================
Shell backtrace (most recent first):
  In annotate at ./annotate_mwe/testAll.sh:28
  In main at ./annotate_mwe/testAll.sh:34
==============================================
Shell backtrace (most recent first):
  In main at ./testall.sh:9
/usr/bin/env: 'python': No such file or directory

Thanks