def _is_cp_helper(self, choi, atol, rtol):
if atol is None:<EOL><INDENT>atol = self._atol<EOL><DEDENT>if rtol is None:<EOL><INDENT>rtol = self._rtol<EOL><DEDENT>return is_positive_semidefinite_matrix(choi, rtol=rtol, atol=atol)<EOL>
Test if a channel is completely-positive (CP)