input: Write a python function to remove duplicates from a list of strings.
  assert remove_duplicates(['Apple', 'Orange', 'Apple', 'Mango', 'Banana', 'Mango'])==['Apple', 'Orange', 'Mango', 'Banana']
  assert remove_duplicates(['Cherry', 'Berry', 'Cherry', 'Berry', 'Cherry'])==['Cherry', 'Berry']
  assert remove_duplicates(['Grape', 'Grape', 'Apple', 'Apple', 'Banana'])==['Grape', 'Apple', 'Banana']
output: def remove_duplicates(strings):
      seen = set()
      result = []
      for string in strings:
          if string not in seen:
              seen.add(string)
              result.append(string)
      return result