unsupported operand type(s) for +: 'int' et 'unicode'

Je travaille avec un templatetag pour retourner la variable à partir d'une formule que j'ai écrite. J'ai essayé de trouver pourquoi j'obtiens ce traceback. J'ai testé la formule dans la coquille et tous fonctionnent correctement. J'ai fait quelques instructions d'impression de l'étiquette et points de vue. Mais ne peut pas comprendre la raison pour cela.

TRACEBACK:

Traceback:
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/core/handlers/base.py" in get_response
117.                             response = middleware_method(request, e)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/core/handlers/base.py" in get_response
111.                         response = callback(request, *callback_args, **callback_kwargs)
File "/Users/urbanrunic/developement/levelend/levelend/levelend/configs/common/../../apps/common/utils/decorators.py" in wrapper
65.                         context_instance=RequestContext(request), mimetype=mimetype)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/shortcuts/__init__.py" in render_to_response
20.     return HttpResponse(loader.render_to_string(*args, **kwargs), **httpresponse_kwargs)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/loader.py" in render_to_string
188.         return t.render(context_instance)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in render
123.             return self._render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in _render
117.         return self.nodelist.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in render
744.                 bits.append(self.render_node(node, context))
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/debug.py" in render_node
73.             result = node.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/loader_tags.py" in render
127.         return compiled_parent._render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in _render
117.         return self.nodelist.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in render
744.                 bits.append(self.render_node(node, context))
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/debug.py" in render_node
73.             result = node.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/loader_tags.py" in render
127.         return compiled_parent._render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in _render
117.         return self.nodelist.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in render
744.                 bits.append(self.render_node(node, context))
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/debug.py" in render_node
73.             result = node.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django_static/templatetags/django_static.py" in render
108.         code = self.nodelist.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in render
744.                 bits.append(self.render_node(node, context))
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/debug.py" in render_node
73.             result = node.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/loader_tags.py" in render
64.             result = block.nodelist.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in render
744.                 bits.append(self.render_node(node, context))
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/debug.py" in render_node
73.             result = node.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/loader_tags.py" in render
64.             result = block.nodelist.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in render
744.                 bits.append(self.render_node(node, context))
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/debug.py" in render_node
73.             result = node.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/defaulttags.py" in render
311.             return self.nodelist_true.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/base.py" in render
744.                 bits.append(self.render_node(node, context))
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/debug.py" in render_node
73.             result = node.render(context)
File "/Users/urbanrunic/.virtualenvs/levelend/lib/python2.6/site-packages/django/template/defaulttags.py" in render
227.                 nodelist.append(node.render(context))
File "/Users/urbanrunic/developement/levelend/levelend/levelend/configs/common/../../apps/lender/templatetags/lender_tags.py" in render
15.         context[self.min] = monthlyPayment(self.how_much, self.apr_min, self.max_repayment_length)
File "/Users/urbanrunic/developement/levelend/levelend/levelend/configs/common/../../apps/lender/utils.py" in monthlyPayment
34.     M = P / ((1 - 1 / (1 + mi) ** n) / mi)
Exception Type: TemplateSyntaxError at /results/
Exception Value: Caught TypeError while rendering: unsupported operand type(s) for +: 'int' and 'unicode'

FORMULE:

def monthlyPayment(P, mi, n):
""" returns monthly payment """
M = P / ((1 - 1 / (1 + mi) ** n) / mi)
return M

TAG:

class MinMonthlyPaymentsNode(Node):
def __init__(self, how_much, apr_min, max_repayment_length, min):
self.how_much, self.apr_min, self.max_repayment_length, self.min = how_much, apr_min, max_repayment_length, min
def render(self, context):
context[self.min] = monthlyPayment(self.how_much, self.apr_min, self.max_repayment_length)
return ''
def do_monthly_payment(parser, token):
"""
returns a monthly payment based on the formula with interst and amount of loan
Example usage:
{% min_monthly_payments how_much, apr_min, max_repayment_length as [min]%}
"""
args = token.contents.split()
if len(args) != 6:
raise TemplateSyntaxError, "min_monthly_payments tag takes exactly six arguments"
if args[4] != 'as':
raise TemplateSyntaxError, "fourth argument to the min_monthly_payments tag must be 'as'"
return MinMonthlyPaymentsNode(args[1], args[2], args[3], args[5])
register.tag('min_monthly_payments', do_monthly_payment)

MODÈLES:

class Lender(TitleAndSlugModel):
"""
A lender
"""
DISBURSED_TYPES = get_namedtuple_choices('DISBURSED_TYPES', (
(0, 'DIRECT_TO_SCHOOL', 'Directly to School'),
(1, 'SENT_TO_YOU', 'Sent to You'),
))
SUITABILITY_TYPES = get_namedtuple_choices('SUITABILITY_TYPES', (
(0, 'UNDERGRADUATE', 'Undergraduate'),
(1, 'GRADUATE', 'Graduate'),
(2, 'LAW', 'Law'),
(3, 'MEDICAL', 'Medical'),
(4, 'PARENTS', 'Parents'),
))
# Financial summary
apr_min = models.DecimalField(max_digits=5, decimal_places=2)
apr_max = models.DecimalField(max_digits=5, decimal_places=2)
# Borrower rewards
auto_debit_discount = models.DecimalField(max_digits=5, decimal_places=2)
auto_debit_discount_note = models.CharField(max_length=250, null=True, blank=True)
additional_rewards_1 = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
additional_rewards_1_note = models.CharField(max_length=250, null=True, blank=True)
additional_rewards_2 = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
additional_rewards_2_note = models.CharField(max_length=250, null=True, blank=True)
# General info
loan_name = models.CharField(max_length=250)
loan_services_by = models.CharField(max_length=250)
funds_disbursed = models.PositiveIntegerField(choices=DISBURSED_TYPES.get_choices(), default=0)
co_signer_release_available = models.IntegerField(null=True, blank=True, help_text="Please enter in months")
suitable_for = MultiSelectField(max_length=50, choices=SUITABILITY_TYPES.get_choices())
external_url = models.URLField(max_length=250)
lender_logo = FileBrowseField("Image", max_length=200, directory="uploads/", extensions=[".jpg"], blank=True, null=True)
schools = models.ManyToManyField(School)
# Repayment
max_repayment_length = models.IntegerField(null=True, blank=True, help_text="Please enter in years")
max_deferral_length = models.IntegerField(null=True, blank=True, help_text="Enter as X months after graduation")
# Rates
interest_rate_index = models.DecimalField(max_digits=5, decimal_places=2)
interest_rate_index_note = models.CharField(max_length=250, null=True, blank=True)
min_repayment_rate = models.DecimalField(max_digits=5, decimal_places=2)
min_repayment_rate_note = models.CharField(max_length=250, null=True, blank=True)
max_repayment_rate = models.DecimalField(max_digits=5, decimal_places=2)
max_repayment_rate_note = models.CharField(max_length=250, null=True, blank=True)
# Fees
origination_fee = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
guarantee_fee = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
# Notes
notes = models.TextField(null=True, blank=True)
def get_absolute_url(self):
return reverse("results_detail", args=[self.slug])
def __unicode__(self):
return "%s" % (self.title)

De nouveau toute aide sera grandement appréciée, même si il est un point dans la bonne direction. Merci!!!!