# Write a Python program to Find all duplicate characters in string from collections import Counter  def find_dup_char(input):      # now create dictionary using counter method    # which will have strings as key and their     # frequencies as value    WC = Counter(input)    j = -1                # Finding no. of  occurrence of a character    # and get the index of it.    for i in WC.values():        j = j + 1        if( i > 1 ):            print WC.keys()[j],  # Driver programif __name__ == "__main__":    input = 'geeksforgeeks'    find_dup_char(input)