Jeff Weaver, former presidential election campaign manager for Sen. Bernie Sanders (I., Vt.), opened up on Tuesday about what he sees as necessary Democratic Party revisions.

Weaver was asked by MSNBC’s Andrea Mitchell about Donna Brazile's new book, Hacks, where the former interim Democratic National Committee chairwoman describes how Hillary Clinton's campaign had a special joint fundraising agreement with the DNC. The agreement allowed her campaign to, in Brazile's words, "control the party’s finances, strategy, and all the money raised" months before any primary vote was cast.

Weaver described the book as filling "in the details of what many of us already knew."

The former Sanders campaign manager further discussed flaws he saw in the Democratic Party's nomination process that resulted in the process being "stacked against" Sanders. He cited, among other examples, Clinton's joint fundraising agreement.

"The joint fundraising agreement was obviously operated in a way that works against us [Sanders campaign]," Weaver said.

When asked about the debate schedule being stacked against Sanders, Weaver said there was "no doubt about that."

On Sunday, current DNC Chairman Tom Perez expressed the need for similar reforms. Perez told Chuck Todd on "Meet The Press" that debates for the 2020 election will be scheduled before they know who the candidates are, and added that the party will have to "earn the trust of the voters."

"The number one goal has to be fair and transparent," Perez said. "All of our fundraising agreements, our partnerships, will be available to everyone as they were actually in 2016."

Weaver added superdelegate reform to the list of changes important to making the process "fair."

"What we have to figure out now is how we make sure none of these things happen again. How we move forward, how we make the process so its fair and perceived to be fair," Weaver said. "That means taking care of superdelegates, reducing superdelegates, opening up primaries and making reforms to the party to make it stronger."

During the 2016 Democratic primaries, superdelegates came under scrutiny for consisting largely of "Democratic elites" who act "as a bulwark against a candidate who might rouse the grassroots and romp the nomination," according to Politico.

The Sanders campaign and its supporters made the argument that the current Democratic primary process gives too much power to party elites, making it possible for them to overturn the will of the voters.

In October, Tom Perez named 75 new members-at-large to the DNC, positions that come with superdelegate votes. The new members will take part in the vote to determine party rules ahead of the 2020 primary. The 75 members consist of lobbyists, political operatives and include at least three people from the Clinton Campaign and Sanders campaign.

Watch Perez's interview on "Meet the Press" here: