Where the execution of the promissory note by the maker is not disputed, the question of whether attestors were present or not at the time of execution is immaterial for determining the document's validity.

PROMISSORY NOTE - ATTESTATION - NOT MANDATORY - A promissory note is not a document required by law to be compulsorily attested. Its validity rests on the signature of the maker and the fulfillment of other requirements under Section 4 of the NI Act.

MATERIAL ALTERATION - SUBSEQUENT ADDITION OF ATTESTORS - Since attestation is not mandatory, the act of obtaining signatures of attestors, even after its execution, does not amount to material alteration under Section 87 of the NI Act, and thus does not vitiate the document.

IMMATERIALITY OF ATTESTORS - Where the execution of the promissory note by the maker is not disputed, the question of whether attestors were present or not at the time of execution is immaterial for determining the document's validity.