Question

Working on a custom lists class in python like

class ListData:
        def __init__(self):
                 self.data = []

        def add(self, x):
                 self.data.append(x)

        def delete(self, x):
                 self.data.remove(x)

When testing, always return None :

from list import ListData

listdata = ListData()


mylist = [34, 32, 34, 89]
mylist = listdata.add(2)
mylist = listdata.add(5)

print mylist # Prints None

Answer 1

You can change your API to be able to print it as a list. you may read the following

Immutable vs Mutable types

class ListData:
        def __init__(self):
                 self.data = []

        def add(self, x):
                 self.data.append(x)

        def delete(self, x):
                 self.data.remove(x)

        def data(self):
            return self.data




a = ListData()
a.add(1)
a.add(2)
print a.data

will output:

[1, 2]