def print_result(statistic):
	op = '9.2f'
	print("""\
count   = {0.count:{op}}
mean    = {0.mean:{op}} 
median  = {0.median:{op}}
mode    = {0.mode[0]:{op}}
std_dev = {0.std_dev:{op}}""").format(statistic, op=op)

count   = {0.count:{op}}
mean    = {0.mean:{op}} 
median  = {0.median:{op}}
mode    = {0.mode[0]:{op}}
std_dev = {0.std_dev:{op}}
Traceback (most recent call last):
  File "str180.py", line 74, in <module>
    main()
  File "str180.py", line 19, in main
    print_result(statistic)
  File "str180.py", line 73, in print_result
    std_dev = {0.std_dev:{op}}""").format(statistic, op=op)
AttributeError: 'NoneType' object has no attribute 'format'

statistic(count=49.0, mean=4.795918367346939, median=4.0, mode=[1.0, 2.0, 3.0], std_dev=2.508149980868491)

def print_result(statistic):
	op = '9.2f'
	print("""\
count   = {0.count:{op}}
mean    = {0.mean:{op}} 
median  = {0.median:{op}}
mode    = {0.mode[0]:{op}}
std_dev = {0.std_dev:{op}}""".format(statistic, op=op))

>>> def print_result(statistic):
...     op = '9.2f'
...     fmt = ('count   = {0.count:{op}}\n'
...            'mean    = {0.mean:{op}}\n'
...            'median  = {0.median:{op}}\n'
...            'mode    = {0.mode[0]:{op}}\n'
...            'std_dev = {0.std_dev:{op}}')
...     out = fmt.format(statistic, op=op)
...     print(out)
... 
>>> class A:
...     count = 1
...     mean = 2
...     median = 3
...     mode = [4, 4, 4]
...     std_dev = 5
... 
>>> print_result(A())
count   =      1.00
mean    =      2.00
median  =      3.00
mode    =      4.00
std_dev =      5.00
>>>