def METHOD_NAME(filename):
    # grab params from input file
    params = dict()
    import amanzi_xml.utils.io
    xml = amanzi_xml.utils.io.fromFile(filename)
    import amanzi_xml.utils.search as search
    #
    #  Material Properties
    #
    strK = search.find_tag_path(xml, ["amanzi_input","materials","material","permeability",]).get('x')
    params["k"] = float(strK)
    strMu = search.find_tag_path(xml, ["amanzi_input","phases","liquid_phase","viscosity",]).text
    params["mu"] = float(strMu)
    strRho = search.find_tag_path(xml, ["amanzi_input","phases","liquid_phase","density",]).text
    params["rho"] = float(strRho)
    #
    #  Boundary Conditions
    #
    strH0 = search.find_tag_path(xml, ["amanzi_input","boundary_conditions","boundary_condition,LeftBC","liquid_phase","liquid_component","hydrostatic",]).get("value")
    params["h_0"] = float(strH0)
    strH1 = search.find_tag_path(xml, ["amanzi_input","boundary_conditions","boundary_condition,RightBC","liquid_phase","liquid_component","hydrostatic",]).get("value")
    params["h_1"] = float(strH1)
    #
    #  Standard Gravity
    #
    params.setdefault("g",9.80665)
    # instantiate the class
    return UnconfinedSeepageHead(params)