How to pass a variable to sp_validateLogin?

Question

MySQL

Hello everyone
When submitting the form, I receive a variable with mail:
_username = request.form['inputEmail']
and pass it on to validation:
cursor.callproc('sp_validateLogin', (_username))
But I throw out an error:
(1318, u'Incorrect number of arguments for PROCEDURE bucketlist.sp_validateLogin; expected 1, got 13')
I suspect that the problem is that he counts the login not as a single entity, but by the number of characters. That is, [email protected] will not be like 1 variable, but 13 different ones.
How can this limitation be bypassed?