Evidence to Interpret Them Drummond argues that the trial court should have allowed extrinsic evidence of the parties’ interpretation of their agreements and evidence of their course of dealing to establish the meaning of those agreements. We disagree. Drummond and United’s intent is clear from the four corners of the 1972, 1991, and 1996 agreements. The parties intended to extend indefinitely the terms of the four original leases. Thus, there is nothing ambiguous about those agreements or about the parties’ intent as expressed in those agreements. Because the agreements were not ambiguous, the trial court properly excluded extrinsic evidence to explain or to supplement the express language of those agreements. See Southland Quality Homes, Inc. v. Williams, 781 So.2d 949 (Ala.2000) (<HOLDING>). General contract law requires a court to
holding if the language of a deed or other written instrument is clear and unambiguous the intention of the parties is gathered from the instrument it is what the grant or said and not what he intended to say holding that the term shall is mandatory for purposes of statutory construction when the statute is unambiguous holding that for purposes of the aggravated assault statute if the instrument used is a firearm as defined by section 7900016 then that instrument is a deadly weapon as a matter of law  regardless of whether it is loaded or capable of being fired and holding that for purposes of the aggravated assault statute if the instrument is not a firearm then courts are to apply an objective test and look to the nature and actual use of the instrument and not to the subjective fear of the victim or intent of the perpetrator in determining whether the instrument is a deadly weapon holding that when a contract is unambiguous the court will enforce the plain meaning of the contract as the intention of the parties recognizing that the primary source for determining whether a contract is clear is the text of the document itself when an instrument is unambiguous it construction and legal effect will be based upon what is found within its four corners