func_code: def intersection(a, b):
      i = 0
      s = []
      while i < len(a) and i < len(b):
          if a[i] in b:
              s.append(a[i])
          i = i + 1
      n = 0
      prev = s[n]
      curr = s[n + 1]
      x = []
      while curr < len(s):
          if curr != prev:
              x.append(prev)
          n = n + 1
      return x