LoadError using julia

New to Julia
1

please, who can help me i got this issue using julia 0.5 in jupyter

UndefVarError: cf not defined

in include_string(::String, ::String) at ./loading.jl:441
in include_string(::String, ::String) at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib:?

2

Seems like cf is simply not defined? Also, how to quote code with backticks.