(a) Every pleading, motion, and legal memorandum of a party represented by an attorney shall be dated and signed by at least one attorney of record in the attorney’s individual name, whose address and Washington State Bar Association membership number shall be stated. A party who is not represented by an attorney shall sign and date the party’s pleading, motion, or legal memorandum and state the party’s address. Petitions for dissolution of marriage, separation, declarations concerning the validity of a marriage, custody, and modification of decrees issued as a result of any of the foregoing petitions shall be verified. Other pleadings need not, but may be, verified or accompanied by affidavit. The signature of a party or of an attorney constitutes a certificate by the party or attorney that the party or attorney has read the pleading, motion, or legal memorandum, and that to the best of the party’s or attorney’s knowledge, information, and belief, formed after an inquiry reasonable under the circumstances: (1) it is well grounded in fact; (2) is warranted by existing law or a good faith argument for the extension, modification, or reversal of existing law or the establishment of new law; (3) it is not interposed for any improper purpose, such as to harass or to cause unnecessary delay or needless increase in the cost of litigation; and (4) the denials of factual contentions are warranted on the evidence or, if specifically so identified, are reasonably based on a lack of information or belief. If a pleading, motion, or legal memorandum is not signed, it shall be stricken unless it is signed promptly after the omission is called to the attention of the pleader or movant. If a pleading, motion, or legal memorandum is signed in violation of this rule, the court, upon motion or upon its own initiative, may impose upon the person who signed it, a represented party, or both, an appropriate sanction, which may include an order to pay to the other party or parties the amount of the reasonable expenses incurred because of the filing of the pleading, motion, or legal memorandum, including a reasonable attorney fee. (b) In helping to draft a pleading, motion or document filed by the otherwise self-represented person, the attorney certifies that the attorney has read the pleading, motion, or legal that the attorney has read the pleading, motion, or legal memorandum, and that to the best of the attorney’s knowledge, information, and belief, formed after an inquiry reasonable under the circumstances: (1) it is well grounded in fact, (2) it is warranted by existing law or a good faith argument for the extension, modification, or reversal of existing law or the establishment of new law, (3) it is not interposed for any improper purpose, such as to harass or to cause unnecessary delay or needless increase in the cost of litigation, and (4) the denials of factual contentions are warranted on the evidence or, if specifically so identified, are reasonably based on a lack of information or belief. The attorney in providing such drafting assistance may rely on the otherwise self-represented person’s representation of facts, unless the attorney has reason to believe that such representations are false or materially insufficient, in which instance the attorney shall make an independent reasonable inquiry into the facts.