docs: def parse(s, element=Element, atomicstring=lambda s: s):
      """
  Translates from ASCIIMathML (an easy to type and highly readable way to
  represent math formulas) into MathML (a w3c standard directly displayable by
  some web browsers).
  
  The function `parse()` generates a tree of elements:
  
      >>> import asciimathml
      >>> asciimathml.parse('sqrt 2')
      <Element math at b76fb28c>
  
  The tree can then be manipulated using the standard python library.  For
  example we can generate its string representation:
  
      >>> from xml.etree.ElementTree import tostring
      >>> tostring(asciimathml.parse('sqrt 2'))
      '<math><mstyle><msqrt><mn>2</mn></msqrt></mstyle></math>'
      """
  
      global Element_, AtomicString_
  
      Element_ = element
      AtomicString_ = atomicstring
  
      s, nodes = parse_exprs(s)
      remove_invisible(nodes)
      nodes = map(remove_private, nodes)
  
      return El('math', El('mstyle', *nodes))