I am familiar with the = filter. == key sequence indents the current line, while gg=G indents the entire file. I am trying to create a command:FixIndentation to get a similar effect, to fix indentation in the entire file.
# vim documentation provides example to map to key
map <F7> gg=G<C-o><C-o>
# my attempt to map to a command fails
command ReIndent execute "gg=G"
:ReIndent
E492: Not an editor command: gg=G