fix: allow echo.cwl to run on python3
fix: allow echo.cwl to run on python3

dleehr/cwltool,dleehr/cwltool,SciDAP/cwltool,common-workflow-language/cwltool,SciDAP/cwltool,SciDAP/cwltool,SciDAP/cwltool,common-workflow-language/cwltool,dleehr/cwltool,dleehr/cwltool,common-workflow-language/cwltool