trying to make bash alias on mac

Question

I am trying to follow this explanation of how to make an alias and made the following .bashrc file in my home directory. Here it is:

# .bashrc

# User specific aliases and functions
alias py='python3'
alias pip='pip3'

# Source global definitions
if [ -f /etc/bashrc ]; then
    . /etc/bashrc
fi

PATH=$PATH:/home/username/bin:/usr/local/homebrew
export PATH

I restarted my shell and ran "py" and got a "command not found" error. What am I doing wrong? Thanks

I tried the following as well:

# .bashrc

# User specific aliases and functions
alias py='/usr/bin/python3'
alias pip='/usr/bin/pip3'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi

PATH=$PATH:/home/username/bin:/usr/local/homebrew
export PATH

as well as:

# .bashrc

# User specific aliases and functions
alias py='/usr/local/bin/python3'
alias pip='/usr/local/bin/pip3'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi

PATH=$PATH:/home/username/bin:/usr/local/homebrew
export PATH

Both of these also gave a "command not found" error.