The following persons cannot be witnesses:
(1) Those who are of unsound mind at the time of their production for examination.
(2) Children under ten (10) years of age, who appear incapable of receiving just impressions of the facts respecting which they are examined, or of relating them truly. At the time a child under the age of ten (10) years of age is called to testify in any court proceeding, the court shall conduct a hearing in chambers to determine whether the child qualifies as a witness under this section. In conducting such hearing the court shall take every reasonable means necessary to prevent intimidation or harassment of the child by the parties or their attorneys. The judge, rather than the parties, shall examine the child but he shall do so in the presence of the parties and he shall pose to the child any reasonable questions requested by the parties and previously submitted to the court. The judge may rephrase any questions so that the child is not intimidated.
(3) Parties or assignors of parties to an action or proceeding, or persons in whose behalf an action or proceeding is prosecuted against an executor or administrator, upon a claim or demand against the estate of a deceased person, as to any communication or agreement, not in writing, occurring before the death of such deceased person.