Suppose that $x, y, z$ are non-zero real numbers such that:
\[
\begin{cases}
  x = 2 - \dfrac{y}{z} \\
  y = 2 - \dfrac{z}{x} \\
  z = 2 - \dfrac{x}{y}.
\end{cases}
\]
Find all possible values of $T = x + y + z$.

Let's think step by step and output the final answer within \boxed{}.
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