old_contents: # -*- coding: utf-8 -*-
  from flask import jsonify, request
  
  from .models import Account
  
  def get_data(request):
      """Get data from request either from form-data or json body"""
      data = request.form
      if not data:
          data = request.get_json()
      return data
  
  def error(message, status=200):
      """Wrap an error message in a response JSON"""
      data = {"status": "error", "reason": message}
      return jsonify(data), status
  
  def check_required_params(params, data):
      for param in params:
          result = check_required_param(param, data)
          if result:
              return result
  
  def check_required_param(param, data):
      """Check if `data` contains mandatory parameter `param`"""
      if not data:
          return error("Missing mandatory parameter {}".format(param))
      try:
          data[param]
      except KeyError:
          return error("Missing mandatory parameter {}".format(param))
      return None
  
  def get_account(param, data):
      """Return account model if account referenced by number in data exists, error otherwise"""
      account = Account.query.filter_by(number=data[param]).first()
      if not account:
          return (None, error("Invalid {} account number {}".format(param, data[param])))
      return (account, None)
  
  def validate_amount(param, data):
      try:
          numeric_amount = float(data[param])
      except ValueError:
          return (None, error("Invalid {} specified: {}. Must be a decimal number, e.g. 123.45.".format(param, data[param]), 400))
      if numeric_amount < 0:
          return (None, error("{} must be a positive decimal number.".format(param, data[param]), 400))
      return (numeric_amount, None)
  
new_contents: # -*- coding: utf-8 -*-
  from flask import jsonify, request
  
  from .models import Account
  
  def get_data(request):
      """Get data from request either from form-data or json body"""
      data = request.form
      if not data:
          data = request.get_json()
      return data
  
  def error(message, status=200):
      """Wrap an error message in a response JSON"""
      data = {"status": "error", "reason": message}
      return jsonify(data), status
  
  def check_required_params(params, data):
      """Check if `data` contains list of mandatory parameters `params`"""
      for param in params:
          result = check_required_param(param, data)
          if result:
              return result
  
  def check_required_param(param, data):
      """Check if `data` contains mandatory parameter `param`"""
      if not data:
          return error("Missing mandatory parameter {}".format(param))
      try:
          data[param]
      except KeyError:
          return error("Missing mandatory parameter {}".format(param))
      return None
  
  def get_account(param, data):
      """Return account model if account referenced by number in data exists, error otherwise"""
      account = Account.query.filter_by(number=data[param]).first()
      if not account:
          return (None, error("Invalid {} account number {}".format(param, data[param])))
      return (account, None)
  
  def validate_amount(param, data):
      """Validate that param in data is a representation of a positive decimal number"""
      try:
          numeric_amount = float(data[param])
      except ValueError:
          return (None, error("Invalid {} specified: {}. Must be a decimal number, e.g. 123.45.".format(param, data[param]), 400))
      if numeric_amount < 0:
          return (None, error("{} must be a positive decimal number.".format(param, data[param]), 400))
      return (numeric_amount, None)
  
subject: Add method documentation