class FileOwners:
@staticmethod
def group_by_owners(files):
g={}
for i,j in files.items():
if j in g.keys():
g[j].append(i)
else:
g.update({j:[]})
g[j].append(i)
return (g)
files = {
'Input.txt': 'Randy',
'Code.py': 'Stan',
'Output.txt': 'Randy'
}
print(FileOwners.group_by_owners(files))