'write style theme'

def _write_style(self, node):

    style = SubElement(node, 'cdr:style')
    ln_ref = SubElement(style, 'a:lnRef', {'xmlns:a': self.schema, 'idx': '2'})
    scheme_clr = SubElement(ln_ref, 'a:schemeClr', {'val': 'accent1'})
    SubElement(scheme_clr, 'a:shade', {'val': '50000'})
    fill_ref = SubElement(style, 'a:fillRef', {'xmlns:a': self.schema, 'idx': '1'})
    SubElement(fill_ref, 'a:schemeClr', {'val': 'accent1'})
    effect_ref = SubElement(style, 'a:effectRef', {'xmlns:a': self.schema, 'idx': '0'})
    SubElement(effect_ref, 'a:schemeClr', {'val': 'accent1'})
    font_ref = SubElement(style, 'a:fontRef', {'xmlns:a': self.schema, 'idx': 'minor'})
    SubElement(font_ref, 'a:schemeClr', {'val': 'lt1'})
