input: Write a function to remove all duplicates from a given array of strings and return the resulting array.
  assert removeDuplicates(['a', 'b', 'a', 'c', 'c', 'd'])==['a', 'b', 'c', 'd']
  assert removeDuplicates(['apple', 'banana', 'apple', 'cherry', 'cherry', 'date'])==['apple', 'banana', 'cherry', 'date']
  assert removeDuplicates(['one', 'one', 'two', 'three', 'two'])==['one', 'two', 'three']
  assert removeDuplicates([])==[]
  assert removeDuplicates(['unique'])==['unique']
output: def removeDuplicates(arr):
      return list(dict.fromkeys(arr))