simplehttp issue

Having this issue
~/simplehttp ‹master›$ go get github.com/snwfdhmp/simplehttp

github.com/spf13/cobra

../go/src/github.com/spf13/cobra/bash_completions.go:22:24: undefined: io.StringWriter
../go/src/github.com/spf13/cobra/bash_completions.go:383:26: undefined: io.StringWriter
../go/src/github.com/spf13/cobra/bash_completions.go:425:24: undefined: io.StringWriter
../go/src/github.com/spf13/cobra/bash_completions.go:437:27: undefined: io.StringWriter
../go/src/github.com/spf13/cobra/bash_completions.go:475:25: undefined: io.StringWriter
../go/src/github.com/spf13/cobra/bash_completions.go:486:20: undefined: io.StringWriter
../go/src/github.com/spf13/cobra/bash_completions.go:501:38: undefined: io.StringWriter
../go/src/github.com/spf13/cobra/bash_completions.go:529:21: undefined: io.StringWriter
../go/src/github.com/spf13/cobra/bash_completions.go:566:28: undefined: io.StringWriter
../go/src/github.com/spf13/cobra/bash_completions.go:591:29: undefined: io.StringWriter