docs: def process_equations(key, value, fmt, meta):
      """Processes the attributed equations."""
  
      if key == 'Math' and len(value) == 3:
  
          # Process the equation
          eq = _process_equation(value, fmt)
  
          # Get the attributes and label
          attrs = eq['attrs']
          label = attrs[0]
          if eq['is_unreferenceable']:
              attrs[0] = ''  # The label isn't needed outside this function
  
          # Context-dependent output
          if eq['is_unnumbered']:  # Unnumbered is also unreferenceable
              return None
          elif fmt in ['latex', 'beamer']:
              return RawInline('tex',
                               r'\begin{equation}%s\end{equation}'%value[-1])
          elif fmt in ('html', 'html5') and LABEL_PATTERN.match(label):
              # Present equation and its number in a span
              text = str(references[label])
              outerspan = RawInline('html',
                                    '<span %s style="display: inline-block; '
                                    'position: relative; width: 100%%">'%(''\
                                    if eq['is_unreferenceable'] \
                                    else 'id="%s"'%label))
              innerspan = RawInline('html',
                                    '<span style="position: absolute; '
                                    'right: 0em; top: %s; line-height:0; '
                                    'text-align: right">' %
                                    ('0' if text.startswith('$') and
                                     text.endswith('$') else '50%',))
              num = Math({"t":"InlineMath"}, '(%s)' % text[1:-1]) \
                if text.startswith('$') and text.endswith('$') \
                else Str('(%s)' % text)
              endspans = RawInline('html', '</span></span>')
              return [outerspan, AttrMath(*value), innerspan, num, endspans]
          elif fmt == 'docx':
              # As per http://officeopenxml.com/WPhyperlink.php
              bookmarkstart = \
                RawInline('openxml',
                          '<w:bookmarkStart w:id="0" w:name="%s"/><w:r><w:t>'
                          %label)
              bookmarkend = \
                RawInline('openxml',
                          '</w:t></w:r><w:bookmarkEnd w:id="0"/>')
              return [bookmarkstart, AttrMath(*value), bookmarkend]
  
      return None