For Python, Guido van Rossum based the grouping of statements on indentation. The reasons for this are explained in the first section of the "Design and History Python FAQ". Colons, :
, are used to declare an indented code block, such as the following example:
class ExampleClass:
#Every function belonging to a class must be indented equally
def __init__(self):
name = "example"
def someFunction(self, a):
#Notice everything belonging to a function must be indented
if a > 5:
return True
else:
return False
#If a function is not indented to the same level it will not be considers as part of the parent class
def separateFunction(b):
for i in b:
#Loops are also indented and nested conditions start a new indentation
if i == 1:
return True
return False
separateFunction([2,3,5,6,1])
The recommended indentation is 4 spaces but tabs or spaces can be used so long as they are consistent. Do not mix tabs and spaces in Python as this will cause an error in Python 3 and can causes errors in Python 2.