I get this error when i try to create invoice. 

Odoo Server Error

Traceback (most recent call last):
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/http.py", line 656, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/http.py", line 314, in _handle_exception
    raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/tools/pycompat.py", line 87, in reraise
    raise value
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/http.py", line 698, in dispatch
    result = self._call_function(**self.params)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/http.py", line 346, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/service/model.py", line 97, in wrapper
    return f(dbname, *args, **kwargs)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/http.py", line 339, in checked_call
    result = self.endpoint(*a, **kw)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/http.py", line 941, in __call__
    return self.method(*args, **kw)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/http.py", line 519, in response_wrap
    response = f(*args, **kw)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/addons/web/controllers/main.py", line 966, in call_button
    action = self._call_kw(model, method, args, {})
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/addons/web/controllers/main.py", line 954, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/api.py", line 759, in call_kw
    return _call_kw_multi(method, model, args, kwargs)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/odoo/api.py", line 746, in _call_kw_multi
    result = method(recs, *args, **kwargs)
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/env/env_zameen/addons/rsms/real_estate/models/file.py", line 353, in create_invoice
    invoice.action_invoice_open()
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/addons/sale/models/account_invoice.py", line 59, in action_invoice_open
    res = super(AccountInvoice, self).action_invoice_open()
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/thirdparty/financials/fiscal/models/fiscal_year.py", line 256, in action_invoice_open
    return super(AccountInvoice, self).action_invoice_open()
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/addons/account/models/account_invoice.py", line 988, in action_invoice_open
    to_open_invoices.action_move_create()
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/thirdparty/financials/account_asset/models/account_invoice.py", line 33, in action_move_create
    result = super(AccountInvoice, self).action_move_create()
  File "/home/syedhamza/custom/programming/enviornments/odoo/odoo12/src/odoo/addons/account/models/account_invoice.py", line 1341, in action_move_create
    move.post(invoice = inv)
TypeError: post() got an unexpected keyword argument 'invoice'

my code:

@api.multi
def create_invoice(self):
    # check duplicity
    list_of_product_id = [x.product_id.id for x in self.file_payment_ids]
    for i in list_of_product_id:
        if list_of_product_id.count(i) > 1:
            raise ValidationError(_("Duplicity of products are not allowed"))
    if self.file_payment_ids:
        prod = [(0, 0, {
            'product_id': rec.product_id.id,
            'name': rec.product_id.name,
            'account_id': rec.product_id.property_account_income_id.id,
            # 'price_unit': rec.value if rec.payment_type == 'fix' else [self.sale_amount * rec.value / 100][0]
            'price_unit': rec.initial_payment,
            # 'is_fully_paid': rec.is_fully_paid
        }) for rec in self.file_payment_ids]

        invoice = self.env['account.invoice'].create({
            'file_id': self, # this id is just for invoice create method i will extract this field from there and push remaining values
            'name': self.name,
            'type' : 'out_invoice',
            'user_id':self.user_id.id,
            'partner_id': self.membership_id.id,
            'account_id': self.membership_id.property_account_receivable_id.id,
            'property_invoice_type': 'initial_payment',
            'date_invoice': self.booking_date,
            'date_due': self.booking_date,
            'invoice_line_ids': prod
        })

        invoice.action_invoice_open()

        self.payment_states = 'open'

        self.history_log('First Owner', invoice.create_date, self.membership_id.id,self.env.user.company_id.partner_id.id)
        self.initial_invoice = False
        self.env['confirmation'].confirmation_popup('Invoice')

Updated my Question:

here's the post method

_inherit = "account.move"

@api.multi
def post(self):
    date_jv = self.date
    fiscal_year_obj = self.env['fiscal.year'].search([('start_date', '<=', date_jv), ('end_date', '>=', date_jv)])
    fiscal_month_obj = self.env['fiscal.month'].search(
        [('open_close', '=', False), ('start_date', '<=', date_jv), ('end_date', '>=', date_jv)])

    if date_jv:
        inv_date = datetime.strptime(date_jv, "%Y-%m-%d")
    else:
        raise ValidationError(
            "Please enter journal entry date!")
    invdate_year = inv_date.year
    if fiscal_year_obj:
        if fiscal_year_obj[0].state != 'closed':
            if fiscal_month_obj:
                if fiscal_month_obj[0].state != 'closed':
                    return super(AccountMove, self).post()
                else:
                    raise ValidationError(
                        "You are trying to access %r fiscal month that is already closed" % fiscal_month_obj[
                            0].name)
            else:
                raise ValidationError("month not found")

        else:
            raise ValidationError(
                "You are trying to access %r fiscal year that is already closed" % fiscal_year_obj[0].name)
    else:
        raise ValidationError("year not found")

I don't know what is wrong. Any help ?