在变量名前后使用“？”，显示关于该对象的概要信息。(jupyter notebook)

def add_numbers(a, b):
    """
    Add two numbers together
    Returns
    -------
    the sum : type of arguments
    """
    return a + b

add_numbers?

Signature: add_numbers(a, b)
Docstring:
Add two numbers together
Returns
-------
the sum : type of arguments
File:      c:\users\dell\<ipython-input-1-a44112c7fc88>
Type:      function

add_numbers??

Signature: add_numbers(a, b)
Source:   
def add_numbers(a, b):
    """
    Add two numbers together
    Returns
    -------
    the sum : type of arguments
    """
    return a + b
File:      c:\users\dell\<ipython-input-1-a44112c7fc88>
Type:      function