'Strip from the left, taking ANSI markers into account.'

def lstrip(self, chars=None):

    clean = self._clean_string
    raw = self._raw_string
    nlen = len(clean)
    nlstripped = (nlen - len(clean.lstrip(chars)))
    lstripped = ''
    (ic, ir1) = (0, 0)
    while nlstripped:
        if (ic >= nlstripped):
            break
        elif (raw[ir1] != clean[ic]):
            lstripped += raw[ir1]
        else:
            ic += 1
        ir1 += 1
    return ANSIString((lstripped + raw[ir1:]))
