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.