dir(instance)
# or (same value)
instance.__dir__()
# or
instance.__dict__

Then you can test what type is with type() or if is a method with callable().

I use __dict__ and dir(<instance>)

Example:

class MyObj(object):
  def __init__(self):
    self.name = 'Chuck Norris'
    self.phone = '+6661'

obj = MyObj()
print(obj.__dict__)
print(dir(obj))

# Output:  
# obj.__dict__ --> {'phone': '+6661', 'name': 'Chuck Norris'}
#
# dir(obj)     --> ['__class__', '__delattr__', '__dict__', '__doc__',
#               '__format__', '__getattribute__', '__hash__', 
#               '__init__', '__module__', '__new__', '__reduce__', 
#               '__reduce_ex__', '__repr__', '__setattr__', 
#               '__sizeof__', '__str__', '__subclasshook__', 
#               '__weakref__', 'name', 'phone']

Use getattr if you have an attribute in string form:

>>> class User(object):
       name = 'John'

>>> u = User()
>>> param = 'name'
>>> getattr(u, param)
'John'

Otherwise use the dot .:

>>> class User(object):
       name = 'John'

>>> u = User()
>>> u.name
'John'

If you want to keep the logic hidden inside the class, you may prefer to use a generalized getter method like so:

class Test:
    def __init__(self):
        self.attr1 = 1
        self.attr2 = 2

    def get(self,varname):
        return getattr(self,varname)

t = Test()
x = "attr1"
print ("Attribute value of {0} is {1}".format(x, t.get(x)))

Outputs:

Attribute value of attr1 is 1

Another apporach that could hide it even better would be using the magic method __getattribute__, but I kept getting an endless loop which I was unable to resolve when trying to get retrieve the attribute value inside that method.

Also note that you can alternatively use vars(). In the above example, you could exchange getattr(self,varname) by return vars(self)[varname], but getattrmight be preferable according to the answer to What is the difference between vars and setattr?.