input: Write a function to remove duplicates from an array of strings and return the resulting array. If the array is empty, return an empty 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', 'world'])==['hello', 'world']
  assert removeDuplicates(['single'])==['single']
  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