Function signed_public_key_from_dir 

fn signed_public_key_from_dir(
    path: impl AsRef<Path>,
) -> Result<SignedPublicKey, Error>

Creates a single [SignedPublicKey] from regular files in a directory.

First collects the paths of all regular files in path. Then parses each regular file as a single OpenPGP packet. Finally, reads a single OpenPGP certificate from the packets.

Errors

Returns an error if

• recursively collecting regular files from path fails,
• parsing a single OpenPGP packet from each collected regular file fails,
• no [SignedPublicKey] can be created from the OpenPGP packets,
• creating a [SignedPublicKey] from the OpenPGP packets fails,
• an additional, unwanted [SignedPublicKey] is created from the OpenPGP packets,
• or creating an additional, unwanted [SignedPublicKey] from the OpenPGP packets fails.