PowerShell function to get specific details for an AD user

Get-Employee.ps1

function Get-Employee {
  param(
    [String]$Username,
    [String]$ProxyAddressesFilter
    )

  If($Username) {
    Get-ADUser -Identity $Username -Properties Department, Title, Manager, Office, LockedOut, officePhone, telephoneNumber
  } Else {
    Get-ADUser -Filter "proxyAddresses -like `"*$($ProxyAddressesFilter)*`"" -Properties Department, Title, Manager, Office, LockedOut, officePhone, telephoneNumber
  }
}