how to return number of certain value in python code example

Example 1: pd count how many item occurs in another column

df['Counts'] = df.groupby(['Color'])['Value'].transform('count')

Example 2: hiw ti count the number of a certain value in python

#using the .count() function where the occurence of an element you 
#want to find is the thing in the paranthesis
lista = [1,1,2,3,4,5]
print(lista.count(1))
# will return 2