'Alert when a service account has too many keys.
return: [list of AuditIssues]'

def _max_keys(self, key_count, error_cat='SA'):

    errors = []
    if (key_count > self.gcp_config.MAX_SERVICEACCOUNT_KEYS):
        ae = make_audit_issue(error_cat, 'MAX', 'KEYS')
        ae.notes = ('Too    Many    Keys    (count:    %s,    max:    %s)' % (key_count, self.gcp_config.MAX_SERVICEACCOUNT_KEYS))
        errors.append(ae)
    return errors
