Use Module and Function instead of Class in Python

The following scripts run in ipython demonstrate the differences between instance method and static method.
Generally OOP make things complicated for imperative style applications.
So when developing this style application (such as command-line application) use functions inside modules, instead of "module - class - method".
The Python standard library is a good example that all utility functions are all common functions not wrapped in classes.

In [1]: cat utils.py
class FileUtils:
    def __init__(self):
        print 'initialize', self

    @staticmethod
    def static_copy(src, dst):
        print 'class copy from', src, 'to', dst

    def instance_copy(self, src, dst):
        print self, 'copy from', src, 'to', dst

In [2]: import utils

In [3]: myutil = utils.FileUtils()
initialize <utils.FileUtils instance at 0x8ab250c>

In [4]: myutil.instance_copy('aa', 'bb')
<utils.FileUtils instance at 0x8ab250c> copy from aa to bb

In [5]: utils.FileUtils().instance_copy('aa', 'bb')
initialize <utils.FileUtils instance at 0x8ab24ec>
<utils.FileUtils instance at 0x8ab24ec> copy from aa to bb

In [6]: utils.FileUtils.static_copy('aa', 'bb')
class copy from aa to bb

In [7]: utils.FileUtils.instance_copy('aa', 'bb')
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-7-cce9f79fc45b> in <module>()
----> 1 utils.FileUtils.instance_copy('aa', 'bb')

TypeError: unbound method instance_copy() must be called with FileUtils instance as first argument (got str instance instead)

In [8]: myutil.static_copy('aa', 'bb')
class copy from aa to bb

Notice the subtle difference between [5] and [6], parenthesis followed the class name is a "instance", while only class name without the following parenthesis is a "class".

Ref: The definitive guide on how to use static, class or abstract methods in Python