code: def concatenate_attributes(attributes):
      '''Concatenate InstanceAttribute to return a bigger one.'''
      # We get a template/
      tpl = attributes[0]
      attr = InstanceAttribute(tpl.name, tpl.shape, 
                               tpl.dtype, tpl.dim, alias=None)
      
      # Special case, not a single array has size bigger than 0
      if all(a.size == 0 for a in attributes):
          return attr
      else: 
          attr.value = np.concatenate([a.value for a in attributes if a.size > 0], axis=0)
          return attf concatenate_attributes(attributes):
      '''Concatenate InstanceAttribute to return a bigger one.'''
      # We get a template/
      tpl = attributes[0]
      attr = InstanceAttribute(tpl.name, tpl.shape, 
                               tpl.dtype, tpl.dim, alias=None)
      
      # Special case, not a single array has size bigger than 0
      if all(a.size == 0 for a in attributes):
          return attr
      else: 
          attr.value = np.concatenate([a.value for a in attributes if a.size > 0], axis=0)
          return attr
docs: Concatenate InstanceAttribute to return a bigger one.