A group of friends (n >= 2) have reunited for a get-together after 
a very long time. 

They agree that they will make presentations on holiday destinations 
or expeditions they have been to only if it satisfies **one simple rule**: 
> the holiday/journey being presented must have been visited _only_ by the presenter and no one else from the audience.

Write a program to output the presentation agenda, including the
presenter and their respective presentation titles. 

---
### EXAMPLES

```python
presentation_agenda([
    {'person': 'Abe', 'dest': ['London', 'Dubai']},
    {'person': 'Bond', 'dest': ['Melbourne', 'Dubai']}
]) == [{'person': 'Abe', 'dest': ['London']},
       {'person': 'Bond', 'dest': ['Melbourne']}]

presentation_agenda([
    {'person': 'Abe', 'dest': ['Dubai']},
    {'person': 'Brad', 'dest': ['Dubai']}
]) == []

presentation_agenda([
    {'person': 'Abe', 'dest': ['London', 'Dubai']},
    {'person': 'Bond', 'dest': ['Melbourne', 'Dubai']},
    {'person': 'Carrie', 'dest': ['Melbourne']},
    {'person': 'Damu', 'dest': ['Melbourne', 'Dubai', 'Paris']}
]) == [{'person': 'Abe',  'dest': ['London']},
       {'person': 'Damu', 'dest': ['Paris']}]

```

Difficulty: EASY
Starter code: def presentation_agenda(friend_list):
	

Solutions:
from collections import Counter

def presentation_agenda(friend_list):
	uniqueDest = {d for (d, c) in Counter((d for p in friend_list for d in p['dest'])).items() if c == 1}
	pFilteredDest = tuple(((p['person'], [d for d in p['dest'] if d in uniqueDest]) for p in friend_list))
	return [{'person': name, 'dest': lst} for (name, lst) in pFilteredDest if lst]


def presentation_agenda(friend_list):
	out = []
	for friend in friend_list:
		p_list = friend['dest']
		for f in friend_list:
			p_list = [loc for loc in p_list if f == friend or loc not in f['dest']]
		if len(p_list):
			out.append({'person': friend['person'], 'dest': p_list})
	return out


from operator import itemgetter
from collections import Counter
from itertools import chain

def presentation_agenda(friend_list):
	okay = {k for (k, v) in Counter(chain.from_iterable(map(itemgetter('dest'), friend_list))).items() if v == 1}.__contains__
	result = []
	for friend in friend_list:
		temp = list(filter(okay, friend['dest']))
		if temp:
			result.append({'person': friend['person'], 'dest': temp})
	return result


def presentation_agenda(friend_list):
	result = []
	for (i, friend) in enumerate(friend_list):
		ds = {x for (j, f) in enumerate(friend_list) if j != i for x in f['dest']}
		xs = [x for x in friend['dest'] if x not in ds]
		if xs:
			result.append({'person': friend['person'], 'dest': xs})
	return result


from functools import reduce

def presentation_agenda(friend_list):

	def add_exclusive_locations(agenda, presenter):

		def is_unique(location):
			return False if any((location in friend['dest'] for friend in filter(lambda f: f != presenter, friend_list))) else True
		exclusive = list(filter(is_unique, presenter['dest']))
		if exclusive:
			agenda.append({'person': presenter['person'], 'dest': exclusive})
		return agenda
	return reduce(add_exclusive_locations, friend_list, [])


from functools import reduce

def presentation_agenda(friend_list):

	def add_exclusive_locations(agenda, friend):

		def is_unique(loc):
			return all((peer == friend or loc not in peer['dest'] for peer in friend_list))
		exclusive = list(filter(is_unique, friend['dest']))
		if exclusive:
			agenda.append({'person': friend['person'], 'dest': exclusive})
		return agenda
	return reduce(add_exclusive_locations, friend_list, [])


from functools import reduce

def presentation_agenda(friend_list):

	def add_exclusive_locations(agenda, friend):
		locations_visited_by_peers = reduce(lambda lst, p: lst + p['dest'] if p != friend else lst, friend_list, [])

		def is_unique(loc):
			return loc not in locations_visited_by_peers
		exclusive = list(filter(is_unique, friend['dest']))
		if exclusive:
			agenda.append({'person': friend['person'], 'dest': exclusive})
		return agenda
	return reduce(add_exclusive_locations, friend_list, [])


from copy import deepcopy

def presentation_agenda(presentation_agenda):
	data = deepcopy(presentation_agenda)
	for person in data:
		B = []
		for p in presentation_agenda:
			if p['person'] != person['person']:
				B += p['dest']
		person['dest'] = sorted(list(set(person['dest']) - set(B)))
	return [person for person in data if person['dest']]


from collections import Counter

def presentation_agenda(friend_list):
	all_dests = sum((friend['dest'] for friend in friend_list), [])
	uniq_dests = [dest for (dest, count) in Counter(all_dests).items() if count == 1]
	agenda = []
	for friend in friend_list:
		uniq = [x for x in friend['dest'] if x in uniq_dests]
		if uniq:
			agenda.append({'person': friend['person'], 'dest': uniq})
	return agenda