You are returning a tuple here:

elif retailer_pk:
    return (request, 'page-retailer-single.html', {
        "products": products,
        "sorting": filt["sorting"],
        "filtering": filt["filtering"],
        "retailer": retailer,
    })

Did you forget to add render there perhaps:

elif retailer_pk:
    return render(request, 'page-retailer-single.html', {
        "products": products,
        "sorting": filt["sorting"],
        "filtering": filt["filtering"],
        "retailer": retailer,
    })

You are not returning a HttpResponse here:

return user_form.errors, restaurant_form.errors

return this instead:

render(request, 'auth/register.html', {'restaurant_form':restaurant_form, 'user_form': user_form})

or rather, you should skip that whole else and return.

The clickjacking middleware is calling the response's get method. Hence, your view is not returning a HttpResponse instance.

This is wrong:

return (request, 'dashboard.html', {'section': 'dashboard'})

You are returning a tuple where you have to return a Response.

Instead of directly returning a response you can use the render-shortcut:

from django.shortcuts import render
from django.contrib.auth.decorators import login_required

@login_required()
def dashboard(request):
    return render(request, 'dashboard.html', {'section': 'dashboard'})

You have an trailing comma left in your return statement in views. Remove that and you'll be fine.

To be precise, upadte the following line from

return HttpResponse("You did it this time!,"),

to

return HttpResponse("You did it this time!,")

The comma at the end is turning the returned object into a tuple. Remove it and you should be fine.

Compare:

>>> def f():
...     return 1,
...
>>> type(f())
<class 'tuple'>

and

>>> def g():
...     return 1
...
>>> type(g())
<class 'int'>

get_or_create does not just return the object:

Returns a tuple of (object, created), where object is the retrieved or created object and created is a boolean specifying whether a new object was created.

In your case d has been assigned this tuple instead of the object you expected, so you get the attribute error. You can fix your code by changing it to:

d, created = DiaSemana.objects.get_or_create(dias=diaSemana)

The following two lines look unnecessary to me. The get_or_create call above ensures that d.dias=diaSemana, so there's no need to assign it again. There's probably no need to call save either.

d.dias = diaSemana;
d.save()

Your post functions returns a 2-tuple, and does not pass the context to the render function. It should be:

return render(
    request,
    'battle.html',
    {'characterID': characterID, 'monsterID': monsterID}
)

Not:

return (render(
        request,
        template_name ='battle.html'
    ),
    {'characterID': characterID, 'monsterID': monsterID}
)

You use a lot of brackets. In Python one normally does not use brackets for simple if statements, etc. So although not wrong, it is more idiomatic to write if request.method == 'POST', than if (request.method == 'POST'):.

Note that you need to implement an else case as well, since the post method should always return a response. Here however the request.method == 'POST' check is not necessary, since Django's class-based views should do proper routing to post and get.