incrementer.py

def incrementer(i=1):
  _l = dict()
  def c(n=None):
    if n:
      _l.setdefault(n, 0)
      _l[n] += i
      return _l[n]
    else:
      return _l
  return c


# In [2]: score = incrementer(10)

# In [3]: score('Steve')
# Out[3]: 10

# In [4]: score('Aaron')
# Out[4]: 10

# In [5]: score('Steve')
# Out[5]: 20

# In [6]: score()
# Out[6]: {'Aaron': 10, 'Steve': 20}