Added docstrings.
Added docstrings.

landlab/landlab,Carralex/landlab,cmshobe/landlab,amandersillinois/landlab,laijingtao/landlab,ManuSchmi88/landlab,amandersillinois/landlab,landlab/landlab,ManuSchmi88/landlab,landlab/landlab,cmshobe/landlab,csherwood-usgs/landlab,Carralex/landlab,csherwood-usgs/landlab,RondaStrauch/landlab,ManuSchmi88/landlab,laijingtao/landlab,cmshobe/landlab,SiccarPoint/landlab,SiccarPoint/landlab,RondaStrauch/landlab,RondaStrauch/landlab,Carralex/landlab