equivalent of pascal's poitners in python

[Nick Perkins]

For Huffman coding you create a binary tree which
stores individual characters at the leaf nodes, and
an integer (for frequency) at both leaf and internal nodes.

I am new to Python, too, so this code may
not be quite right.  Maybe it will be enough for
someone else to fix up.

class HuffmanNode():

    def __init__(self, ch, freq):
        self.ch=ch
        self.freq=freq
        self.left=None
        self.right=None

    def __init__(self, node1, node2):
        self.ch=None
        self.freq = node1.freq + node2.freq
        self.left=node1
        self.right=node2

The point is, like java, there is no such thing as a pointer
because any number of variables can represent the same
object, just as if they were pointers to the same object.

Perhaps someone else could also sketch out the
tree-building proceedure:
1) create a node for each character in the source text
    with it's frequency of occurrence, and store in a collection
2) remove the 2 least-frequent nodes from the collection,
    and join them with a new common parent.
3) put the new parent node back in the collection
4) repeat steps 2,3 until all nodes form a single tree

I think this could be done in very  few lines of code,
but as I said, I just started looking python, too.