parameters: (self, requirement, parent)
docstring: Called when adding a new requirement into the resolve criteria.
  
          :param requirement: The additional requirement to be applied to filter
              the available candidaites.
          :param parent: The candidate that requires ``requirement`` as a
              dependency, or None if ``requirement`` is one of the root
              requirements passed in from ``Resolver.resolve()``.
docstring_summary: Called when adding a new requirement into the resolve criteria.
docstring_tokens: Called when adding a new requirement into the resolve criteria .
function: def adding_requirement(self, requirement, parent):
          """Called when adding a new requirement into the resolve criteria.
  
          :param requirement: The additional requirement to be applied to filter
              the available candidaites.
          :param parent: The candidate that requires ``requirement`` as a
              dependency, or None if ``requirement`` is one of the root
              requirements passed in from ``Resolver.resolve()``.
          """
function_tokens: def adding_requirement ( self , requirement , parent ) :