<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def field_name_exist(self, field_name):
 """Check if there is already a field_name field in the current class It is useful before allowing to rename a field to check name does not already exist. """


        fields = self.class_item.get_fields()
        for f in fields:
            if f.name == field_name:
                return True
        return False