convert excel cellname to index python

1Function columnNumber(colLetter As String) As Integer
2
3    Dim colNumber As Integer
4    Dim i As Integer
5
6    colLetter = UCase(colLetter)
7    colNumber = 0
8    For i = 1 To Len(colLetter)
9        colNumber = colNumber + (Asc(Mid(colLetter, Len(colLetter) - i + 1, 1)) - 64) * 26 ^ (i - 1)
10    Next
11
12    columnNumber = colNumber
13
14End Function