code: def string_to_char(l):
      '''Convert 1-D list of strings to 2-D list of chars.'''
  
      if not l:
          return []
  
      if l == ['']:
          l = [' ']
  
      maxlen = reduce(max, map(len, l))
      ll = [x.ljust(maxlen) for x in l]
      result = []
      for s in ll:
          result.append([x for x in s])
      return resulf string_to_char(l):
      '''Convert 1-D list of strings to 2-D list of chars.'''
  
      if not l:
          return []
  
      if l == ['']:
          l = [' ']
  
      maxlen = reduce(max, map(len, l))
      ll = [x.ljust(maxlen) for x in l]
      result = []
      for s in ll:
          result.append([x for x in s])
      return result
docs: Convert 1-D list of strings to 2-D list of chars.