'Attempt to find a dependency named `name` at version `version`. If version is None, return the "default" version as determined using a
symbolic link (if found). Returns a triple of: env_script, base_path, real_version'

def resolve(self, requirement, **kwds):

    (name, version, type) = (requirement.name, requirement.version, requirement.type)
    if ((version is None) or self.versionless):
        exact = ((not self.versionless) or (version is None))
        return self._find_dep_default(name, type=type, exact=exact, **kwds)
    else:
        return self._find_dep_versioned(name, version, type=type, **kwds)
