in - 'a' in ['a','b','c']
getattr - getattr(os, 'remove') to get something from a module
predicate(lambda) - lambda x: x % 2 == 0
map(func, list) - return a list of results of calling func to each member of list
"%03d" % 1
repr(str) : if needs to generate code, repr() escape string so safe to be put into code or in expr
programmatic import: try:... __import__(module_name, fromlist=[''])... except ImportError: (read __import__ doc, the result depend on fromlist which is very stupid)
module explore: import parent will not see child in dir(parent), only import parent.child show child in dir(parent)
inspect.ismodule
isinstance(obj, class)