code: func (q *Query) And(field string) *Criterion {
  	if !startsUpper(field) {
  		panic("The first letter of a field in a bolthold query must be upper-case")
  	}
  
  	q.currentField = field
  	return &Criterion{
  		query: q,
  	}
  }
docs: // And creates a nother set of criterion the needs to apply to a query