How to highlight dataframe columns

[SriRajesh]

Hi,
I have below dataframe, I want to highlight P with green, F with red.
df:

  c1 c2 c3
A P  na P  
B F  F  P
C P  P  na

and write to excel.
I use below code,

df.conditional_format('B2:D4', {'type': '2_color_scale'})
    
df.to_excel("output.xlsx", sheet_name=sheet1)

giving below error:
AttributeError: 'DataFrame' object has no attribute 'conditional_format'