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: difflib.go
    path of file: ./repos/goreportcard/vendor/github.com/prometheus/client_golang/prometheus/internal
    
    the code of the file until where you have to start completion: // Copyright 2022 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// It provides tools to compare sequences of strings and generate textual diffs.
//
// Maintaining `GetUnifiedDiffString` here because original repository
// (https://github.com/pmezard/go-difflib) is no loger maintained.
package internal

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"strings"
)

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func calculateRatio(matches, length int) float64 {
	if length > 0 {
		return 2.0 * float64(matches) / float64(length)
	}
	return 1.0
}

type Match struct {
	A    int
	B    int
	Size int
}

type OpCode struct {
	Tag byte
	I1  int
	I2  int
	J1  int
	J2  int
}

// Sequen
    
func (m *SequenceMatcher) GetMatchingBlocks() []Match {
	if m.matchingBlocks != nil {
		return m.matchingBlocks
	}

	var matchBlocks func(alo, ahi, blo, bhi int, matched []Match) []Match
	matchBlocks = func(alo, ahi, blo, bhi int, matched []Match) []Match {
		match := m.findLongestMatch(alo, ahi, blo, bhi)
		i, j, k := match.A, match.B, match.Size
		if match.Size > 0 {
			if alo < i && blo < j {
				matched = matchBlocks(alo, i, blo, j, matched)
			}
			matched = append(matched, match)
			if i+k < ahi && j+k < bhi {
				matched = matchBlocks(i+k, ahi, j+k, bhi, matched)
			}
		}
		return matched
	}
	matched := matchBlocks(0, len(m.a), 0, len(m.b), nil)

	// It's possible that we have adjacent equal blocks in the
	// matching_blocks list now.
	nonAdjacent := []Match{}
	i1, j1, k1 := 0, 0, 0
	for _, b := range matched {
		// Is this block adjacent to i1, j1, k1?
		i2, j2, k2 := b.A, b.B, b.Size
		if i1+k1 == i2 && j1+k1 == j2 {
			// Yes, so collapse them -- this just increases the length of
			// the first block by the length of the second, and the first
			// block so lengthened remains the block to compare against.
			k1 += k2
		} else {
			// Not adjacent.  Remember the first block (k1==0 means it's
			// the dummy we started with), and make the second block the
			// new block to compare against.
			if k1 > 0 {
				nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
			}
			i1, j1, k1 = i2, j2, k2
		}
	}
	if k1 > 0 {
		nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
	}

	nonAdjacent = append(nonAdjacent, Match{len(m.a), len(m.b), 0})
	m.matchingBlocks = nonAdjacent
	return m.matchingBlocks
}