code: def is_pinned(self):
          # type: () -> bool
          
          specifiers = self.specifier
          return (len(specifiers) == 1 and
                  next(iter(specifiers)).operator in {'==', '==='})
docs: Return whether I am pinned to an exact version.
  
          For example, some-package==1.2 is pinned; some-package>1.2 is not.