Printing anagrams together using List and Dictionary

def allAnagram(input):

dict = {}

for strVal in input:

key = ''.join(sorted(strVal))

if key in dict.keys():

dict[key].append(strVal)

else:

dict[key] = []

dict[key].append(strVal)

output = ""

for key,value in dict.items():

output = output + ' '.join(value) + ' '

return output

if __name__ == "__main__":

input=['cat', 'dog', 'tac', 'god', 'act']

print (allAnagram(input))