Question: Using this preamble:

```
\documentclass[pdftex,11pt,a4paper,openany]{memoir}
\usepackage[brazil]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{indentfirst}
\usepackage{latexsym}
\usepackage{amsmath,amssymb,amsfonts,wasysym}
\usepackage[pdftex]{graphicx}
\usepackage{wrapfig}
\usepackage[left=3cm,right=2cm,top=3cm,bottom=3cm]{geometry}
\usepackage{color}
\usepackage[dvipsnames]{xcolor}
\definecolor{darkgray}{gray}{0.3}
\setcounter{secnumdepth}{3}
\setcounter{tocdepth}{3}
\usepackage[pdftex, colorlinks=true, linkcolor=darkgray, citecolor=blue, urlcolor=blue]{hyperref}

```

TexMaker gives this error message:

```
! LaTeX Error: Command \newfloat already defined.
Or name \end... illegal, see p.192 of the manual.

```

Where is the problem?

Answer: 
It's not a good idea to redefine `\item`, as it's used in many parts of LaTeX. Here is a `\benumerate` environment in which you can use the `\bolditem` command alternating it to the normal one.

```
\documentclass[a4paper]{article}

\let\ifbolditem\iffalse
\def\bolditemtrue{\global\let\ifbolditem\iftrue}
\def\bolditemfalse{\global\let\ifbolditem\iffalse}

\newenvironment{benumerate}
  {\def\bolditem{\bolditemtrue\item}%
   \enumerate
   \renewcommand\makelabel[1]{\hss\llap{\ifbolditem\bfseries\fi##1\bolditemfalse}}}
  {\endenumerate}

\begin{document}
\begin{benumerate}
\item Normal
\bolditem Bold
\item Normal again
\bolditem[9] Bold
\end{benumerate}
\end{document}

```
By using `enumerate` package you can also use this command.

```
\documentclass{article}
\usepackage{enumerate}
\begin{document}
    \begin{enumerate}[\bfseries a.]
        \item one
        \item two
        \item three
    \end{enumerate}
\end{document}

```