Notebooks MethodError: length

[tigre200]

I have started following the course, and read through the first two notebooks. In both I get the following error that disables some of the code examples in the notebooks:

Failed to show value:

MethodError: no method matching length(::Nothing)

Closest candidates are:

length(!Matched::BitSet)

@ Base bitset.jl:348

length(!Matched::Base.AsyncGenerator)

@ Base asyncmap.jl:390

length(!Matched::RegexMatch)

@ Base regex.jl:285

...

Stack trace

Here is what happened, the most recent locations are first:

    _similar_shape(itr::Nothing, ::Base.HasLength) @ [array.jl:710](https://github.com/JuliaLang/julia/tree/bd47eca2c8aacd145b6c5c02e47e2b9ec27ab456/base/array.jl#L710)
    _array_for(::Type{Core.MethodInstance}, itr::Nothing, isz::Base.HasLength) @ [array.jl:726](https://github.com/JuliaLang/julia/tree/bd47eca2c8aacd145b6c5c02e47e2b9ec27ab456/base/array.jl#L726)
    _method_instances(f_type::Any, t_type::Any) @ Tricks.jl:136
    #s1#1 @ Tricks.jl:20
    var"#s1#1"(T::Any, ::Any, f::Any, t::Any) @ 
    (::Core.GeneratedFunctionStub)(::UInt64, ::LineNumberNode, ::Any, ::Vararg{Any}) @ boot.jl:602
    content(x::HypertextLiteral.Result) @ convert.jl:91
    show(io::IOContext{IOBuffer}, m::MIME{Symbol("text/html")}, toc::PlutoUI.TableOfContentsNotebook.TableOfContents) @ TableOfContents.jl:502