<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _serialize(self, value, attr, obj):
 """Convert the Arrow object into a string."""

        if isinstance(value, arrow.arrow.Arrow):
            value = value.datetime

        return super(ArrowField, self)._serialize(value, attr, obj)