The relationship between any such bank, trust company or safe deposit company having and maintaining safe deposit boxes for public use and the user or users of such boxes shall be that of lessor and lessee, respectively. In the absence of a written contract to the contrary, the lessee shall be deemed by law to be in possession of such box and the contents thereof. The lessor shall not be charged with knowledge of the contents of any such box. The lessor may limit its liability to the lessee by provisions contained within a lease agreement, but the lessor shall be liable for the acts of its officers and employees for failure to exercise ordinary care.