i=7
type(i)  #class 'int'
repr(int) #class 'int'
type(i) is int #true
type(i)(78) #78

i.__class__ #int
i.__class__.__class__ #type
i.__class__.__class__.__class__ #type
issubclass(type,object) #True

i = 7
dir(i)
getattr(i,'denominator')
a.denominator

A context-manager ensures that resources are properly and automatically managed.

with expression as x:
  body

important: the value of expression.__enter__ is bound to x, not the value of expression. exception information is passed to __exit__()

class LoggingContextManager:
  def __enter__(self):
    return "123"
  def __exit__(self,exc_type,exc_val):
    return

from lcm import *
with LoggingContextManager() as x:
  print(x)  #123

__exit__() can check type for None to see if an exception was thrown

By default __exit__() propagates exceptions thrown from the with-statement's code block.

If __exit__() returns False, the exception is propagated.

By default functions return None. None evaluates to False.
__exit__() should never explicitly re-raise exceptions.