input: Write a function to identify the characters in a given alphabet string and return them as a list. The input alphabet is a string containing all characters of the given alphabet.
  
  assert identify_characters('ABCDEFGHIJKLMNOPQRSTUVWXYZ')==['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
  assert identify_characters('abcdefghijklmnopqrstuvwxyz')==['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
  assert identify_characters('')==[]
output: def identify_characters(alphabet):
      return list(alphabet)