how to insert int in string statements using format code example

Example 1: insert into string python

def insert (source_str, insert_str, pos):
    return source_str[:pos]+insert_str+source_str[pos:]

Example 2: insert into string python

>>> line = 'Kong Panda'
>>> index = line.find('Panda')
>>> output_line = line[:index] + 'Fu ' + line[index:]
>>> output_line
'Kong Fu Panda'