Fish Shell의 vf 프로젝트

저는 물고기 껍질에 가상 물고기를 사용하고 있으므로 vf project projectName이 작업을 시도하면 다음 오류가 발생합니다.

vf 프로젝트 pytube

fish: Unknown command 'virtualenv'
/Users/userName/clones/virtualfish/virtual.fish (line 152):     virtualenv $argv $VIRTUALFISH_HOME/$envname
                                                                        ^
in function '__vf_new',
    called on line 52 of file '/Users/userName/clones/virtualfish/virtual.fish',
    with parameter list 'pytube'

in . (source) call of file '-',
    called on line 85 of file '/Users/userName/clones/virtualfish/virtual.fish',

in function 'vf',
    called on line 43 of file '/Users/userName/clones/virtualfish/projects.fish',
    with parameter list 'new pytube'

in function '__vf_project',
    called on line 52 of file '/Users/userName/clones/virtualfish/virtual.fish',
    with parameter list 'pytube'

in . (source) call of file '-',
    called on line 85 of file '/Users/userName/clones/virtualfish/virtual.fish',

in function 'vf',
    called on standard input,
    with parameter list 'project pytube'

Error: The virtualenv wasn't created properly.
virtualenv returned status 127.

OSx를 사용하고 있는데 이 오류가 발생합니다.