Thanks to Anatoliy Chakkaev for pointing it out.
Closes GH-841.
### verifier.verify(cert, signature, signature_format='binary')
Verifies the signed data by using the `cert` which is a string containing
-the PEM encoded public key, and `signature`, which is the previously calculates
+the PEM encoded certificate, and `signature`, which is the previously calculates
signature for the data, in the `signature_format` which can be `'binary'`, `'hex'` or `'base64'`.
Returns true or false depending on the validity of the signature for the data and public key.