Buggy python submission (verdict: Runtime Error):
n = int(input())

class cell:
    def __init__(self, data, before, _next):
        self.data = data
        self.before = before
        self._next = _next

def search(ddl, data):
    for ind,item in enumerate(ddl):
        if item.data == data:
            return ind
    return None

def getItem(ddl, index):
    if len(ddl) > index and index >= 0:
        return ddl[index]
    return None

ddl = []
for i in range(n):
    inp = input().split()
    if len(inp) == 2:
        op, data = inp
        data = int(data)
    else: op, data = inp[0], None
    if op == 'insert':
        if len(ddl) == 0:
            _next = None
        else:
            _next = ddl[0]
        c = cell(data, None, _next)
        ddl = [c] + ddl
    elif op == 'delete':
        ind = search(ddl, data)
        if ind != None:
            ddl[ind - 1].next = getItem(ddl, ind + 1)
            if getItem(ddl, ind+1) is not None:
                ddl[ind + 1].prev = getItem(ddl, ind - 1)
            ddl = ddl[:ind] + ddl[ind+1:]
    elif op == 'deleteFirst':
        ddl = ddl[1:]
        ddl[0].prev = None
    elif op == 'deleteLast':
        ddl = ddl[:-1]
        ddl[-1]._next = None

print(' '.join([str(item.data) for item in ddl]))

Fixed submission:
from collections import deque
from sys import stdin
n = int(input())
line = stdin.readlines()
ddl = deque()
for i in range(n):
    inp = line[i].split()
    if len(inp) == 2:
        op, data = inp
        data = int(data)
    else: op, data = inp[0], None
    if op == 'insert':
        ddl.appendleft(data,)
    elif op == 'delete':
        try:
            ddl.remove(data)
        except ValueError:
            pass
    elif op == 'deleteFirst':
        ddl.popleft()
    elif op == 'deleteLast':
        ddl.pop()

print(' '.join([str(item) for item in ddl]))

Buggy python submission (verdict: Runtime Error):
n = int(input())

class cell:
    def __init__(self, data, before, _next):
        self.data = data
        self.before = before
        self._next = _next

def search(ddl, data):
    for ind,item in enumerate(ddl):
        if item.data == data:
            return ind
    return None

def getItem(ddl, index):
    if len(ddl) > index and index >= 0:
        return ddl[index]
    return None

ddl = []
for i in range(n):
    inp = input().split()
    if len(inp) == 2:
        op, data = inp
        data = int(data)
    else: op, data = inp[0], None
    if op == 'insert':
        if len(ddl) == 0:
            _next = None
        else:
            _next = ddl[0]
        c = cell(data, None, _next)
        ddl = [c] + ddl
    elif op == 'delete':
        ind = search(ddl, data)
        if ind != None:
            ddl[ind - 1].next = getItem(ddl, ind + 1)
            if getItem(ddl, ind+1) is not None:
                ddl[ind + 1].prev = getItem(ddl, ind - 1)
            ddl = ddl[:ind] + ddl[ind+1:]
    elif op == 'deleteFirst':
        ddl = ddl[1:]
        ddl[0].prev = None
    elif op == 'deleteLast':
        ddl = ddl[:-1]
        if len(ddl) != 0:
         ddl[-1]._next = None

print(' '.join([str(item.data) for item in ddl]))

Fixed submission:
from collections import deque
from sys import stdin
n = int(input())
line = stdin.readlines()
ddl = deque()
for i in range(n):
    inp = line[i].split()
    if len(inp) == 2:
        op, data = inp
        data = int(data)
    else: op, data = inp[0], None
    if op == 'insert':
        ddl.appendleft(data,)
    elif op == 'delete':
        try:
            ddl.remove(data)
        except ValueError:
            pass
    elif op == 'deleteFirst':
        ddl.popleft()
    elif op == 'deleteLast':
        ddl.pop()

print(' '.join([str(item) for item in ddl]))

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())

class cell:
    def __init__(self, data, before, _next):
        self.data = data
        self.before = before
        self._next = _next

def search(ddl, data):
    for ind,item in enumerate(ddl):
        if item.data == data:
            return ind
    return None

def getItem(ddl, index):
    if len(ddl) > index and index >= 0:
        return ddl[index]
    return None

ddl = []
for i in range(n):
    inp = input().split()
    if len(inp) == 2:
        op, data = inp
        data = int(data)
    else: op, data = inp[0], None
    if op == 'insert':
        if len(ddl) == 0:
            _next = None
        else:
            _next = ddl[0]
        c = cell(data, None, _next)
        ddl = [c] + ddl
    elif op == 'delete':
        ind = search(ddl, data)
        if ind != None:
            ddl[ind - 1].next = getItem(ddl, ind + 1)
            if getItem(ddl, ind+1) is not None:
                ddl[ind + 1].prev = getItem(ddl, ind - 1)
            ddl = ddl[:ind] + ddl[ind+1:]
    elif op == 'deleteFirst':
        ddl = ddl[1:]
        if len(ddl) != 0:
            ddl[0].prev = None
    elif op == 'deleteLast':
        ddl = ddl[:-1]
        if len(ddl) != 0:
         ddl[-1]._next = None

print(' '.join([str(item.data) for item in ddl]))

Fixed submission:
from collections import deque
from sys import stdin
n = int(input())
line = stdin.readlines()
ddl = deque()
for i in range(n):
    inp = line[i].split()
    if len(inp) == 2:
        op, data = inp
        data = int(data)
    else: op, data = inp[0], None
    if op == 'insert':
        ddl.appendleft(data,)
    elif op == 'delete':
        try:
            ddl.remove(data)
        except ValueError:
            pass
    elif op == 'deleteFirst':
        ddl.popleft()
    elif op == 'deleteLast':
        ddl.pop()

print(' '.join([str(item) for item in ddl]))

Buggy python submission (verdict: Runtime Error):
from collections import deque
from sys import stdin
n = int(input())
ddl = deque()
for i in stdin:
    inp = i.split()
    if len(inp) == 2:
        op, data = inp
        data = int(data)
    else: op, data = inp[0], None
    if op == 'insert':
        ddl.appendleft(data,)
    elif op == 'delete':
        ddl.remove(data)
    elif op == 'deleteFirst':
        ddl.popleft()
    elif op == 'deleteLast':
        ddl.pop()

print(' '.join([str(item) for item in ddl]))

Fixed submission:
from collections import deque
from sys import stdin
n = int(input())
line = stdin.readlines()
ddl = deque()
for i in range(n):
    inp = line[i].split()
    if len(inp) == 2:
        op, data = inp
        data = int(data)
    else: op, data = inp[0], None
    if op == 'insert':
        ddl.appendleft(data,)
    elif op == 'delete':
        try:
            ddl.remove(data)
        except ValueError:
            pass
    elif op == 'deleteFirst':
        ddl.popleft()
    elif op == 'deleteLast':
        ddl.pop()

print(' '.join([str(item) for item in ddl]))