def add_child(self, child, rangecheck=False):
assert self.seqid == child.seqid,(<EOL>'<STR_LIT>'.format(<EOL>self.fid, self.seqid, child.seqid<EOL>)<EOL>)<EOL>if rangecheck is True:<EOL><INDENT>assert self._strand == child._strand,('<STR_LIT>'.format(self.fid))<EOL>assert self._range.contains(child._range),(<EOL>'<STR_LIT>'<EOL>'<STR_LIT>'.format(self.fid, child.start, child.end)<EOL>)<EOL><DEDENT>if self.children is None:<EOL><INDENT>self.children = list()<EOL><DEDENT>self.children.append(child)<EOL>self.children.sort()<EOL>
Add a child feature to this feature.