Using a value from dropdown box not displaying dataframe

I have copied a sample of dropdown box but not displaying
the dropdown is correctly displayed and values All an creators are available
but in none case : the df or subset of df based on x is not returned

df=%sql select creator, name from sysibm.systables
def view(x):
if x==‘All’ : return df
return df[df[‘CREATOR’]==x]
w = widgets.Select(options=items)
thanks for all update
best regards, Guy