input: Write a function to remove all duplicates from a given array of strings and return the resulting array. The function should return the unique elements in the order they first appeared in the original array. If the input array is empty, the function should return an empty array as well.
  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(['apple', 'banana', 'apple', 'cherry', 'banana'])==['apple', 'banana', 'cherry']
  assert removeDuplicates(['x', 'y', 'z', 'x', 'y', 'z'])==['x', 'y', 'z']
  assert removeDuplicates([])==[]
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