How to create a dataframe in which one column's input is dynamic and derived via an IF statement dependent on another entry in that column

I am looking to convert a two column Excel table which uses IF statements to calculate values in the second column, in to a Pandas dataframe.

Column A figures are static.

Column B figures are dynamic (with the exception of B5 which always remains 100%) and are calculated in Excel with the following IF statement (row 5 being the starting/reference point):

B4 =IF((B5*(1+Variable_1))<2, B5*(1+Variable_1), 2)

B3 =IF((B4*(1+Variable_1))<2, B4*(1+Variable_1), 2)

B2 =IF((B3*(1+Variable_1))<2, B3*(1+Variable_1), 2)

...and so on.

Variable_1 = a percentage (in this example 5%) which used when column A is negative.

When column A switches to positive i.e. >0% (A5), the IF statement changes to:

B6 =IF((B5*(1-Variable_2))>0, B5*(1-Variable_2), 0)

B7 =IF((B6*(1-Variable_2))>0, B6*(1-Variable_2), 0)

… and so on.

Variable_2 is also a percentage and is used when column B is positive (in this example it is also 5%).

I'm a complete amateur when it comes to Python but im hoping someone out there can assist me with something which is rather easy to do in Excel! Many thanks in advance.