defining a class Queue
class Queue : NEW_LINE INDENT def __init__ ( self ) : NEW_LINE INDENT self . queue = [ ] NEW_LINE DEDENT def put ( self , item ) : NEW_LINE INDENT self . queue . append ( item ) NEW_LINE DEDENT def get ( self ) : NEW_LINE INDENT if len ( self . queue ) < 1 : NEW_LINE INDENT return None NEW_LINE DEDENT return self . queue . pop ( 0 ) NEW_LINE DEDENT def front ( self ) : NEW_LINE INDENT return self . queue [ 0 ] NEW_LINE DEDENT def size ( self ) : NEW_LINE INDENT return len ( self . queue ) NEW_LINE DEDENT def empty ( self ) : NEW_LINE INDENT return not ( len ( self . queue ) ) NEW_LINE DEDENT DEDENT