new_contents: #Kunal Gautam
  #Codewars : @Kunalpod
  #Problem name: Simple Fun #204: Smallest Integer
  #Problem level: 7 kyu
  
  from itertools import groupby, chain
  def smallest_integer(matrix):
      min = pos = 0
      for key,_ in groupby([x for x in sorted(list(chain.from_iterable(matrix))) if x>=0]): 
          if key==min:
              min+=1
              pos+=1
          else:
              return min
      return min
  
subject: Create simple_fun_#204_smallest_integer.py