<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi all,<div class=""><br class=""></div><div class="">I’m trying to add a new quantity to a halo catalog following the docs as such, </div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(51, 187, 200); background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #afad24" class=""> 23 </span><span style="font-variant-ligatures: no-common-ligatures; color: #5230e1" class=""><b class="">def</b></span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures" class="">_total_mass</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(halo):</span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #afad24" class=""> 24 </span><span style="font-variant-ligatures: no-common-ligatures" class=""> gasmass, dmmass = halo.data_object.quantities.total_mass()</span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #afad24" class=""> 25 </span><span style="font-variant-ligatures: no-common-ligatures" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #5230e1" class=""><b class="">return</b></span><span style="font-variant-ligatures: no-common-ligatures" class=""> gasmass+dmmass</span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #afad24" class=""> 26 </span><span style="font-variant-ligatures: no-common-ligatures" class=""> </span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #afad24" class=""> 27 </span><span style="font-variant-ligatures: no-common-ligatures" class="">add_quantity(</span><span style="font-variant-ligatures: no-common-ligatures; color: #34bc26" class="">'total_mass'</span><span style="font-variant-ligatures: no-common-ligatures" class="">,_total_mass)</span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #afad24" class=""> 28 </span><span style="font-variant-ligatures: no-common-ligatures" class="">hc.add_quantity(</span><span style="font-variant-ligatures: no-common-ligatures; color: #34bc26" class="">'total_mass’</span><span style="font-variant-ligatures: no-common-ligatures" class="">)</span></div></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-family: Helvetica; font-size: 12px;" class="">however, it seems at add_quantity is not defined. How do I go about doing this?</span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-family: Helvetica; font-size: 12px;" class=""><br class=""></span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-family: Helvetica; font-size: 12px;" class="">Cheers,</span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-family: Helvetica; font-size: 12px;" class="">DK</span></div><div style="margin: 0px; font-stretch: normal; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);" class=""><span style="font-family: Helvetica; font-size: 12px;" class=""><br class=""></span></div></body></html>