---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-4-3b5c3059c8da> in <module>
      1 p = 3
      2 
----> 3 sl = gelatize(laplace, p)
      4 sm = gelatize(mass, p)
      5 

~/CODES/PYCCEL/gelato/gelato/expr.py in gelatize(a, degrees, n_elements, evaluate, mapping, human, expand)
     34 
     35     # ... compute tensor form
---> 36     expr = TensorExpr(a, mapping=mapping, expand=expand)
     37     # ...
     38 

~/CODES/PYCCEL/sympde/sympde/expr/evaluation.py in __new__(cls, *args, **options)
   1054 
   1055         if options.pop('evaluate', True):
-> 1056             r = cls.eval(*args, **options)
   1057         else:
   1058             r = None

~/CODES/PYCCEL/sympde/sympde/expr/evaluation.py in eval(cls, *_args, **kwargs)
   1151 
   1152             # ... # TODO improve
-> 1153             terminal_expr = TerminalExpr(expr, domain)[0]
   1154             # ...
   1155 

~/CODES/PYCCEL/sympde/sympde/expr/evaluation.py in __new__(cls, expr, domain, **options)
    496 
    497         if options.pop('evaluate', True):
--> 498             r = cls.eval(expr, domain)
    499         else:
    500             r = None

~/.local/lib/python3.8/site-packages/sympy/core/cache.py in wrapper(*args, **kwargs)
     92             def wrapper(*args, **kwargs):
     93                 try:
---> 94                     retval = cfunc(*args, **kwargs)
     95                 except TypeError:
     96                     retval = func(*args, **kwargs)

~/CODES/PYCCEL/sympde/sympde/expr/evaluation.py in eval(cls, expr, domain)
    525         """."""
    526 
--> 527         dim = domain.dim
    528         if isinstance(expr, Add):
    529             args = [cls.eval(a, domain=domain) for a in expr.args]

AttributeError: 'NoneType' object has no attribute 'dim'