str: path to the private key used by Ansible to connect to virtual
        machines (by default looks for a file with name
        :attr:`key_name <tmdeploy.config.CloudSection.key_name>` in ``~/.ssh``
        directory)

def key_file_private(self):
        '''str: path to the private key used by Ansible to connect to virtual
        machines (by default looks for a file with name
        :attr:`key_name <tmdeploy.config.CloudSection.key_name>` in ``~/.ssh``
        directory)
        '''
        if not hasattr(self, '_key_file_private'):
            self.key_file_private = '~/.ssh/{key}'.format(key=self.key_name)
        return self._key_file_private