mybinder pasting .jl into new notebook give errors

[paradocs]

Start Pluto in mybinder, then "Create a new notebook"
We paste in a previously saved notebook and run it.

1. We get an error in cell 1 because
   using Markdown
   using InteractiveUtils
   do not have begin end
   Solution: Add begin end for default using statements.
2. Again with pasting a previously saved notebook:
   we must delete the last two cells named
   PLUTO_PROJECT_TOML_CONTENTS
   PLUTO_MANIFEST_TOML_CONTENTS
   I believe that these entries are recreated.
   We can have our students delete these cells before
   saving but it would be nice if this was automated.

Thank you for making Pluto notebooks a great
teaching tool for easy use at many levels.

[fonsp]

Accidental duplicate of JuliaPluto/PlutoTest.jl#30 (comment)