>>> type(None)
<class 'NoneType'>
>>> bool(1)
True
>>> bool(o)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'o' is not defined
>>> bool(0)
False
>>> bool(42)
True
>>> bool(-42)
True
>>> bool(0.0)
False
>>> bool(1.0)
True
>>> ##zero is falsy, nonzero is truthy
>>> bool("")
False
>>> bool("ewq")
True
>>> #empty strings are falsy
>>> bool([])
False
>>> bool([5])
True
>>> bool((,))
  File "<stdin>", line 1
    bool((,))
          ^
SyntaxError: invalid syntax
>>> 
>>> bool((1,2,3))
True
>>> bool(5,)
True
>>> bool((5,))
True
>>> dir()
['__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__']
>>> x = 5
>>> dir()
['__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__', 'x']
>>> #symbol table: dictionary of all variables and their values.
>>> y = 4
>>> print(x + y)
9
>>> dir()
['__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__', 'x', 'y']
>>> x
5
>>> y
4
>>> ## We only see the global frame (scope)
>>>