insertAfter throws "TypeError: NoneType"

[Grepnold]

I have a large XML file representing text.  Page tags contain line tags, line tags contain individual-char tags, each with many attributes.

I'm trying to correct this and need to insert new char tags at places between existing ones.

I have a valid char Tag - at least PyDev tells me it's is, called insertTag, and I'm trying to insert a new char tag after it. 

insertTag.insertAfter(aCopy)

This throws "TypeError: 'NoneType' object is not callable"

I save the actual parse tree Tag as a value in a python list, and assign it to insertTag.  But it points to a soup Tag object.
aCopy is a deep copy made from a nearby char tag as a template, which I then change.  In case it needs to be in the parse tree before the insert, I've also tried
 inserting soup.new_tag(aCopy) which gives the same error.

This happens the first time, not an edge case.

Here's the real code

    insertTag = aList[aStart + common - 1]  # insertion point, insert after this

      for i in range(common, pLen):

        # Clone the last existing tag
        aCopy = copy.copy(aList[aStart + common - 1])
        aCopy.string = pSub[i] # change the string contents
        aCopy['added'] = 1  # mess about with attributes
        ## at this point, insertTag and aCopy are both of type Tag
        insertTag.insertAfter(aCopy) # throws TypeError
        insertTag = aCopy # next insert goes after this one

In short, I have an apparently valid tag from a soup document, and I can't insert another apparently valid tag after it.  What am I doing wrong?

[Grepnold]

Oh dear, how embarrassing.  There is no insertAfter method of Tag.

 insertTag.insert_after(aCopy) runs fine.

I'll delete the topic in a day or two if I have permission to.