Python - Extra Excel chart series with win32com

I'm writing some code for an assignment, and I need to create a simple column chart in Excel. This afternoon I found win32com (amazing tool by the way), but I've been suffering from either the lack of documentation about it, or my lack of luck to find it ^^

I'm playing around with the charts, and I think I've managed to do what I want, with a little exception: the function I wrote always creates 2 series of columns.

This is what I've got:

xlBook = xlApp.Workbooks.Add()

xlSheet = xlBook.Sheets(1)
xlSheet.Name = "Algoritmos de Busqueda"
xlSheet.Cells(1,1).Value="Secuencial"
xlSheet.Cells(2,1).Value="Binaria"
xlSheet.Cells(1,2).Value="32"
xlSheet.Cells(2,2).Value="32"

chart = xlApp.Charts.Add()
chart.Name= "Grafico "+xlSheet.Name
series = chart.SeriesCollection().NewSeries()
valoresx=xlSheet.Range("A1:A2")
valoresy=xlSheet.Range("B1:B2")
series.XValues= valoresx
series.Values= valoresy
series.Name= "Algoritmos"
xAxis= chart.Axes()[0]
yAxis= chart.Axes()[1]
xAxis.HasMajorGridlines = True
yAxis.HasMajorGridlines = True

I create a new series inside the chart, and it contains all the info I need. However, when I run the script, I end up with an Excel chart with 4 columns, with the same info (in pairs). I've done everything I can, but I just can't find what's creating this second series of values on the X axis...

I greatly appreciate any help ^^ Thanks!

By observing the behavior of recording a macro in Excel which performs the same actions as we are replication in Python we can see that there does not appear to be a need to create a new series such as

series = chart.SeriesCollection().NewSeries()

I was able to simply reference an existing series

series = chart.SeriesCollection(1)

The following code seems to give me the desired behavior on my computer.

import win32com.client
xlApp = win32com.client.Dispatch('Excel.Application')

xlBook = xlApp.Workbooks.Add()

xlSheet = xlBook.Sheets(1)
xlSheet.Name = "Algoritmos de Busqueda"
xlSheet.Cells(1,1).Value="Secuencial"
xlSheet.Cells(2,1).Value="Binaria"
xlSheet.Cells(1,2).Value="32"
xlSheet.Cells(2,2).Value="32"

chart = xlApp.Charts.Add()
chart.Name= "Grafico "+xlSheet.Name
series = chart.SeriesCollection(1)
series.XValues= xlSheet.Range("A1:A2")
series.Values= xlSheet.Range("B1:B2")
series.Name= "Algoritmos"
chart.Axes()[0].HasMajorGridlines = True

This has been simplified to the bare minimum. I tested this in Python 2.7 with Excel 2003.