'Define expression to be ignored (e.g., comments) while doing pattern
matching; may be called repeatedly, to define multiple comment or other
ignorable patterns.'

def ignore(self, other):

    if isinstance(other, basestring):
        other = Suppress(other)
    if isinstance(other, Suppress):
        if (other not in self.ignoreExprs):
            self.ignoreExprs.append(other)
    else:
        self.ignoreExprs.append(Suppress(other.copy()))
    return self
