human
Solve the following python programming problem given the following code:
def _calculate_sources(self, thrift_targets, target_filter) : 
    sources = set () 
    def collect_sources(target) : 
        if target_filter (target) : 
            sources.update (target.sources_relative_to_buildroot ()) 
for target in target : 
        target.walk (collect_sources) 
return sources 

    
    

    Fix the buggy line: for target in target :
assistant
#Here is Python code to fix the buggy line: for target in target :
.

for target in thrift_targets :