XML : Python parse XML has multiple root

I failed to parse an XML file(it is GC history). Sample of the XML is shown below.

  <?xml version="1.0" ?>    <verbosegc xmlns="http://www.ibm.com/j9/verbosegc" version="R28_jvm.28_20150612_0201_B252774_CMPRSS">    <initialized id="1" timestamp="2015-12-04T20:17:07.219">    <attribute name="gcPolicy" value="-Xgcpolicy:gencon" />    <attribute name="maxHeapSize" value="0x20000000" />    <attribute name="initialHeapSize" value="0x400000" />  </initialized>    <cycle-start id="4" type="scavenge" contextid="0" timestamp="2015-12-04T20:17:10.677" intervalms="3457.977" />  <gc-start id="5" type="scavenge" contextid="4" timestamp="2015-12-04T20:17:10.677">    <mem-info id="6" free="3037768" total="4194304" percent="72">    </mem-info>  </gc-start>  <gc-end id="8" type="scavenge" contextid="4" durationms="0.807" usertimems="0.000" systemtimems="0.000" timestamp="2015-12-04T20:17:10.678" activeThreads="2">    <mem-info id="9" free="3163968" total="4194304" percent="75">    </mem-info>  </gc-end>  <cycle-end id="10" type="scavenge" contextid="4" timestamp="2015-12-04T20:17:10.678" />  <cycle-start id="16" type="scavenge" contextid="0" timestamp="2015-12-04T20:17:10.742" intervalms="64.838" />  <gc-start id="17" type="scavenge" contextid="16" timestamp="2015-12-04T20:17:10.742">    <mem-info id="18" free="3037664" total="4194304" percent="72">    </mem-info>  </gc-start>   <gc-end id="20" type="scavenge" contextid="16" durationms="0.649" usertimems="0.000" systemtimems="0.000" timestamp="2015-12-04T20:17:10.743" activeThreads="2">    <mem-info id="21" free="3110592" total="4194304" percent="74">    </mem-info>  </gc-end>  <cycle-end id="22" type="scavenge" contextid="16" timestamp="2015-12-04T20:17:10.743" />  <allocation-satisfied id="23" threadId="0000000002E10500" bytesRequested="416" />      </verbosegc>    

I want to mem-info::free in gc-start and gc-end, both of which are enclosed by cycle-start and cycle-end tags and have the same contexid. For example, the first two mem-info values are 3037768 and 3163968, the corresponding contextid is 4 which equals to the cycle-start id. With these data, I can draw the figure to show memory footprint.

The main problem for me is that I could not parse the XML sucessfully with the method in XML parse python because the XML has more than one roots. The getRoot method can only get the first element in the XML. Is there any other solutions for this? thanks