When using MultiMarkdown with LaTeX output, it is common to have multiple front matter keys for inputting files, as shown in the usage guide:
latex input: mmd-memoir-header
Title: MultiMarkdown Example
Base Header Level: 2
latex mode: memoir
latex input: mmd-memoir-begin-doc
latex footer: mmd-memoir-footer
Attempting to extract the latex input key from the command line will only print the first value, with no method for accessing the subsequent latex input fields.