how to merge two keys in dict python code example

Example: python merge two dictionaries in a single expression

z = {**x, **y}  #python 3.5 and above

z = x | y    #python 3.9+ ONLY

def merge_two_dicts(x, y): # python 3.4 or lower
      z = x.copy()   # start with x's keys and values
      z.update(y)    # modifies z with y's keys and values & returns None
      return z