Given a partial main.py and PlaneQueue class in PlaneQueue.py, write the push() and pop() methods for PlaneQueue. Then complete main.py to read in whether flights are arriving or have landed at an airport. An "arriving" flight is pushed onto the queue. A "landed" flight is popped from the front of the queue. Output the queue after each plane is pushed or popped. Entering -1 exits the program. Ex: If the input is:   arriving AA213 arriving DAL23 arriving UA628 landed -1   the output is: (see image attached)     main.py from PlaneQueue import PlaneQueue from PlaneNode import PlaneNode   if __name__ == "__main__":   plane_queue = PlaneQueue()       # TODO: Read in arriving flight codes and whether a flight has landed.    #    Print the queue after every push() or pop() operation. If the user   #    entered "landed", print which flight has landed. Continue until -1    #    is read.   PlaneNode.py class PlaneNode:   def __init__(self, flight_code='0'):     self.flight_code = flight_code     self.next = None         def print_node_data(self):     print(self.flight_code, end='')   PlaneList.py class PlaneList:   def __init__(self):     self.head = None     self.tail = None     def append(self, new_node):     if self.head == None:       self.head = new_node       self.tail = new_node     else:       self.tail.next = new_node       self.tail = new_node     def prepend(self, new_node):     if self.head == None:       self.head = new_node       self.tail = new_node     else:       new_node.next = self.head       self.head = new_node     def insert_after(self, current_node, new_node):     if self.head == None:       self.head = new_node       self.tail = new_node     elif current_node is self.tail:       self.tail.next = new_node       self.tail = new_node     else:       new_node.next = current_node.next       current_node.next = new_node           def remove_after(self, current_node):     # Special case, remove head     if (current_node == None) and (self.head != None):       succeeding_node = self.head.next       self.head = succeeding_node         if succeeding_node == None: # Remove last item         self.tail = None     elif current_node.next != None:       succeeding_node = current_node.next.next       current_node.next = succeeding_node       if succeeding_node == None: # Remove tail         self.tail = current_node     def search(self, key):     position = 1     cur_node = self.head     while cur_node != None:       if cur_node.data == key:         cur_node.node_pos = position         return cur_node       cur_node = cur_node.next       position += 1       def print_list(self):     cur_node = self.head     while cur_node != None:       cur_node.print_node_data()       print()       cur_node = cur_node.next   PlanbeQueue.py from PlaneList import PlaneList   class PlaneQueue:   def __init__(self):     self.plane_list = PlaneList()     self.length = 0       # TODO: Write push() and pop() methods. push() adds an item to the queue   #    and adds 1 to length. pop() removes and returns the first item in    #    the queue and subtracts 1 from length.       def is_empty(self):     return self.length == 0         def print_queue(self):     print('Air-traffic control queue')     if not self.is_empty():       print('  Next to land:', end=' ')       cur_node = self.plane_list.head       cur_node.print_node_data()       print()               if self.length > 1:         print('  Arriving flights:')         cur_node = cur_node.next         while cur_node is not None:           print('   ', end='')           cur_node.print_node_data()           print()           cur_node = cur_node.next     else:       print('Queue is empty.')     print()

Given a partial main.py and PlaneQueue class in PlaneQueue.py, write the push() and pop() methods for PlaneQueue. Then complete main.py to read in whether flights are arriving or have landed at an airport.

• An "arriving" flight is pushed onto the queue.
• A "landed" flight is popped from the front of the queue.

Output the queue after each plane is pushed or popped. Entering -1 exits the program.

Ex: If the input is:

arriving AA213

arriving DAL23

arriving UA628

landed

-1

the output is: (see image attached)

main.py

from PlaneQueue import PlaneQueue

from PlaneNode import PlaneNode

if __name__ == "__main__":

  plane_queue = PlaneQueue()

  # TODO: Read in arriving flight codes and whether a flight has landed. 

  #    Print the queue after every push() or pop() operation. If the user

  #    entered "landed", print which flight has landed. Continue until -1 

  #    is read.

PlaneNode.py

class PlaneNode:

  def __init__(self, flight_code='0'):

    self.flight_code = flight_code

    self.next = None

  def print_node_data(self):

    print(self.flight_code, end='')

PlaneList.py

class PlaneList:

  def __init__(self):

    self.head = None

    self.tail = None

  def append(self, new_node):

    if self.head == None:

      self.head = new_node

      self.tail = new_node

    else:

      self.tail.next = new_node

      self.tail = new_node

  def prepend(self, new_node):

    if self.head == None:

      self.head = new_node

      self.tail = new_node

    else:

      new_node.next = self.head

      self.head = new_node

  def insert_after(self, current_node, new_node):

    if self.head == None:

      self.head = new_node

      self.tail = new_node

    elif current_node is self.tail:

      self.tail.next = new_node

      self.tail = new_node

    else:

      new_node.next = current_node.next

      current_node.next = new_node

  def remove_after(self, current_node):

    # Special case, remove head

    if (current_node == None) and (self.head != None):

      succeeding_node = self.head.next

      self.head = succeeding_node  

      if succeeding_node == None: # Remove last item

        self.tail = None

    elif current_node.next != None:

      succeeding_node = current_node.next.next

      current_node.next = succeeding_node

      if succeeding_node == None: # Remove tail

        self.tail = current_node

  def search(self, key):

    position = 1

    cur_node = self.head

    while cur_node != None:

      if cur_node.data == key:

        cur_node.node_pos = position

        return cur_node

      cur_node = cur_node.next

      position += 1

  def print_list(self):

    cur_node = self.head

    while cur_node != None:

      cur_node.print_node_data()

      print()

      cur_node = cur_node.next

PlanbeQueue.py

from PlaneList import PlaneList

class PlaneQueue:

  def __init__(self):

    self.plane_list = PlaneList()

    self.length = 0

  # TODO: Write push() and pop() methods. push() adds an item to the queue

  #    and adds 1 to length. pop() removes and returns the first item in 

  #    the queue and subtracts 1 from length.

  def is_empty(self):

    return self.length == 0

  def print_queue(self):

    print('Air-traffic control queue')

    if not self.is_empty():

      print('  Next to land:', end=' ')

      cur_node = self.plane_list.head

      cur_node.print_node_data()

      print()

      if self.length > 1:

        print('  Arriving flights:')

        cur_node = cur_node.next

        while cur_node is not None:

          print('   ', end='')

          cur_node.print_node_data()

          print()

          cur_node = cur_node.next

    else:

      print('Queue is empty.')

    print()