In a simple language, seed method is used to initialize the pseudorandom number generator in Python. The seed value is used as a base by the random module to generate a random number.
Here is a simple example for you:
import random
random.seed( 3 )
print "Random number with seed 3 : ", random.random() #will generate a random number
#in order to use the same random number once again in your program, just do
random.seed( 3 )
random.random() # same random number as before
You can use the following video tutorials to clear all your doubts:-