code: def solve(self, value, filter_):
          
  
          args, kwargs = filter_.get_args_and_kwargs()
          source = self.registry[value]
          return source.solve(value, filter_.name, args, kwargs)
docs: Returns the value of an attribute of the value, or the result of a call to a function.
  
          Arguments
          ---------
          value : ?
              A value to solve in combination with the given filter.
          filter_ : dataql.resource.Filter
              An instance of ``Filter`` to solve with the given value.
  
          Returns
          -------
          Depending on the source, the filter may ask for an attribute of the value, or for the
          result of a call to a standalone function taking the value as first argument.
          This method returns this attribute or result.
  
          Example
          -------
  
          >>> from dataql.solvers.registry import Registry
          >>> registry = Registry()
          >>> from datetime import date
          >>> registry.register(date, ['day', 'strftime'])
          >>> solver = FilterSolver(registry)
          >>> solver.solve(date(2015, 6, 1), Filter(name='day'))
          1
          >>> from dataql.resources import PosArg
          >>> solver.solve(date(2015, 6, 1), Filter(name='strftime', args=[PosArg('%F')]))
          '2015-06-01'