Python Math Functions #4 || Python Round -- Python Tutorial

In this python video tutorial cleared explained about Python Math functions like :
1) Python ceil - Round up float in python
2) Python Floor - Round down float in python
3) Python Round - Rounding numbers in python, Round to nearest Integer of any float , Round float to 2 decimal points or also can be used to round to 2 decimal places
4) Python Float Precision - Round float to nearest Integer
5) Python Sqrt - Square root of Number
6) Python Log function - Logarithm of Number
7) Python int function - Converting Float to Integer
8) Absolute of a number

[Diodbutiken]

how can i round a?
***
json_obj = urllib2.urlopen(url)
data = json.load(json_obj)
a =
print a
***
getting error "float is required"