You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: genesis.go
    path of file: ./repos/evmos/x/erc20/types
    
    the code of the file until where you have to start completion: // Copyright Tharsis Labs Ltd.(Evmos)
// SPDX-License-Identifier:ENCL-1.0(https://github.com/evmos/evmos/blob/main/LICENSE)

package types

import "fmt"

// NewGenesisState creates a new genesis state.
func NewGenesisState(params Params, pairs []TokenPair) GenesisState {
	return GenesisState{
		Params:     params,
		TokenPairs: pairs,
	}
}

// DefaultGenesisState sets default evm genesis state with empty accounts and
// 
    
func (gs GenesisState) Validate() error {
	seenErc20 := make(map[string]bool)
	seenDenom := make(map[string]bool)

	for _, b := range gs.TokenPairs {
		if seenErc20[b.Erc20Address] {
			return fmt.Errorf("token ERC20 contract duplicated on genesis '%s'", b.Erc20Address)
		}
		if seenDenom[b.Denom] {
			return fmt.Errorf("coin denomination duplicated on genesis: '%s'", b.Denom)
		}

		if err := b.Validate(); err != nil {
			return err
		}

		seenErc20[b.Erc20Address] = true
		seenDenom[b.Denom] = true
	}

	return gs.Params.Validate()
}