Please explain how to alter text with python code?

[navneet]

# Complete the following remove_dollar function 
# so that it removes any dollar signs and spaces
# and then returns the string as a number (float).
def remove_dollar(s):

csv file data is :

Output:
LastSpend Spend
$144.5 $596
4502.2 $761.6

how can we write a program that removes $ from the column values i.e. LastSpend and Spend