Returns the name of the shared library file compiled for the wrapper
        subroutines coded in fortran.

def libname(self):
        """Returns the name of the shared library file compiled for the wrapper
        subroutines coded in fortran.
        """
        if self.library is not None:
            return "ftypes.{}.so".format(self.library)
        else:
            return "{}.so".format(self.name)