if nan -> find value in cell above Pandas

[zarize]

Hi guys,

I have excel file like this:

Sometext_here
nan
nan
nan
nan
nan
nan
nan
TotallyNewThing
nan
nan
nan

How can i replace nan values? I want to replace them with VALUE above them if not nan
I am struggling with this :(

I have tried this:

for index, value in enumerate(survey):
    if value == '' or (isinstance(value, float) and  math.isnan(value)):
        value = value[index-1]
    print(value)

TypeError: 'float' object is not subscriptable