3.30.2 operator +=

OEQMol &operator+=(OEQMol &lhs, const OEQMol &rhs)
OEQMol &operator+=(OEQMol &lhs, const OEQMolBase &rhs)

These methods concatenate a query molecule given on the right hand side of the operator onto the end of the query molecule on the left hand side of the operator.