class Kramdown::Converter::Latex

def inner(el, opts)

Return the converted content of the children of +el+ as a string. 
def inner(el, opts)
  result = +''
  options = opts.dup.merge(parent: el)
  el.children.each_with_index do |inner_el, index|
    options[:index] = index
    options[:result] = result
    result << send("convert_#{inner_el.type}", inner_el, options)
  end
  result
end