<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def parse_yaml(self, y):
        '''Parse a YAML specification of a target port into this object.'''
        super(TargetPort, self).parse_yaml(y)
        self.port_name = y['portName']
        return self