input: def removeDuplicates(arr: List[str]) -> List[str]:
      """Remove all duplicates from a given array of strings and return the resulting array.
      >>> removeDuplicates(['a', 'b', 'a', 'c', 'c', 'd'])
      ['a', 'b', 'c', 'd']
      >>> removeDuplicates(['apple', 'banana', 'apple', 'cherry', 'banana'])
      ['apple', 'banana', 'cherry']
      """
output:     seen = set()
      result = []
      for item in arr:
          if item not in seen:
              seen.add(item)
              result.append(item)
      return result