NuGet.Commands.SourcesCommand.UpdatePackageSource C# (CSharp) Method

        private void UpdatePackageSource()
        {
            if (String.IsNullOrEmpty(Name))
            {
                throw new CommandLineException(NuGetResources.SourcesCommandNameRequired);
            }

            List<PackageSource> sourceList = _sourceProvider.LoadPackageSources().ToList();
            int existingSourceIndex = sourceList.FindIndex(ps => Name.Equals(ps.Name, StringComparison.OrdinalIgnoreCase));
            if (existingSourceIndex == -1)
            {
                throw new CommandLineException(NuGetResources.SourcesCommandNoMatchingSourcesFound, Name);
            }
            var existingSource = sourceList[existingSourceIndex];

            if (!String.IsNullOrEmpty(Source) && !existingSource.Source.Equals(Source, StringComparison.OrdinalIgnoreCase))
            {
                if (!PathValidator.IsValidSource(Source))
                {
                    throw new CommandLineException(NuGetResources.SourcesCommandInvalidSource);
                }

                // If the user is updating the source, verify we don't have a duplicate.
                bool duplicateSource = sourceList.Any(ps => String.Equals(Source, ps.Source, StringComparison.OrdinalIgnoreCase));
                if (duplicateSource)
                {
                    throw new CommandLineException(NuGetResources.SourcesCommandUniqueSource);
                }
                existingSource = new PackageSource(Source, existingSource.Name);
            }

            ValidateCredentials();

            sourceList.RemoveAt(existingSourceIndex);
            existingSource.UserName = UserName;
            existingSource.Password = Password;
            
            sourceList.Insert(existingSourceIndex, existingSource);
            _sourceProvider.SavePackageSources(sourceList);
            Console.WriteLine(NuGetResources.SourcesCommandUpdateSuccessful, Name);
        }