def _convert_amb_verbal_form( analysis ):
    ''' Converts ambiguous verbal categories of the input analysis. 
        Performs one-to-many conversions. '''
    assert FORM in analysis, '(!) The input analysis does not contain "'+FORM+'" key.'
    results = []
    for root_pat, pos, form_pat, replacements in _amb_verb_conversion_rules:
        if analysis[POSTAG] == pos and re.match(root_pat, analysis[ROOT]) and \
           re.match(form_pat, analysis[FORM]):
           for replacement in replacements:
               new_analysis = copy_analysis_dict( analysis )
               new_form = re.sub(form_pat, replacement, analysis[FORM])
               new_analysis[FORM] = new_form
               results.append( new_analysis )
           # break after the replacement has been made
           # ( to avoid over-generation )
           break
    if not results:
       results.append( analysis )
    return results
Converts ambiguous verbal categories of the input analysis. 
        Performs one-to-many conversions.