Python data science

Question

def missing(df,column_name):
##Start Code
df[df.gender.isnull().sum()]
## End Code

this is th erro
ipython-input-28-6e164c723942> in <module>
----> 1 missing(df,'gender')

<ipython-input-25-01108b799fe1> in missing(df, column_name)
1 def missing(df,column_name):

Answer 1

mm you can sum null values?