title: Use of python module like math.ceil in qweb template in ODOO 11
body: <pre><code>&lt;xpath expr="//*[@id='wrap']/section[2]/div" position="replace"&gt;
      &lt;t t-set="Math" t-value="math"/&gt;
      &lt;t t-foreach="range(0, Math.ceil(number_of_device_issue/2))" t-as="num"&gt;
      &lt;t t-esc="num"/&gt;
  &lt;/t&gt;
  </code></pre>
  
  <p></p>
  
  <p>Error : 'NoneType' object has no attribute 'ceil'
  Traceback (most recent call last):
    File "/home/sachin/Documents/ODOO_11/sources/odoo11-1104/odoo/addons/base/ir/ir_qweb/qweb.py", line 341, in _compiled_fn
      return compiled(self, append, new, options, log)
    File "", line 1, in template_336_8
    File "", line 2, in body_call_content_7
  AttributeError: 'NoneType' object has no attribute 'ceil'</p>
  
  <p>Error to render compiling AST
  AttributeError: 'NoneType' object has no attribute 'ceil'
  Template: 336
  Path: /templates/t/t/div/section[2]/t[2]
  Node: <code>&lt;t t-foreach="range(0, Math.ceil(number_of_device_issue/2))" t-as="num"&gt;
                      &lt;t t-esc="num"/&gt;
                  &lt;/t&gt;</code></p>