
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Given the function $f(x) = \frac{a \cdot 2^{x} - 1}{2^{x} + 1}$, where $a$ is a real number.
1. Discuss the parity of the function $y = f(x)$ based on the different values of $a$ and explain the reason.
2. If for any $x \geqslant 1$, we have $1 \leqslant f(x) \leqslant 3$, find the range of values for $a$.

Present the answer in LaTex format: \boxed{Your answer}
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