input: Write a function to remove all duplicates from an array of strings and return the resulting array.
  def removeDuplicates(arr):
   result = [] 
    
   # traverse for all elements 
   for i in arr: 
    
    # check if exists in result 
    if i not in result: 
     result.append(i) 
    
   # return result 
   return result
  
  assert removeDuplicates(['a', 'b', 'a', 'c', 'c', 'd']) == ['a', 'b', 'c', 'd']
  assert removeDuplicates(['hello', 'world', 'hello', 'universe']) == ['hello', 'world', 'universe']
  assert removeDuplicates([]) == []
  assert removeDuplicates(['unique']) == ['unique']
  assert removeDuplicates(['duplicate', 'duplicate', 'duplicate']) == ['duplicate']
output: def removeDuplicates(arr):
   result = [] 
    
   # traverse for all elements 
   for i in arr: 
    
    # check if exists in result 
    if i not in result: 
     result.append(i) 
    
   # return result 
   return result