input: Write a python function to find common keys in two dictionaries.
  assert intersect({"a": 1, "b": 2, "c": 3}, {"b": 4, "c": 5, "d": 6}) == ["b", "c"]
  assert intersect({"key1": "value1", "key2": "value2"}, {"key2": "value3", "key3": "value4"}) == ["key2"]
  assert intersect({"apple": 1, "banana": 2}, {"orange": 3, "apple": 4}) == ["apple"]
output: def intersect(dict1, dict2):
      return [key for key in dict1 if key in dict2]