<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def well_fields(self, well_x=1, well_y=1):
 """All ScanFieldData elements of given well. Parameters well_x : int well_y : int Returns ------- list of lxml.objectify.ObjectifiedElement All ScanFieldData elements of given well. """

        xpath = './ScanFieldArray/ScanFieldData'
        xpath += _xpath_attrib('WellX', well_x)
        xpath += _xpath_attrib('WellY', well_y)
        return self.root.findall(xpath)