src/HeaderTrait.php
public function getHeader($name)
    {

        // map column => attribute name
        $name = $this->mapAttributeCodeByHeaderMapping($name);

        // query whether or not, the header is available
        if (isset($this->headers[$name])) {
            return $this->headers[$name];
        }

        // throw an exception, if not
        throw new \InvalidArgumentException(sprintf('Header %s is not available', $name));
    }
public function getHeader($name)
    {

        // map column => attribute name
        $name = $this->mapAttributeCodeByHeaderMapping($name);

        // query whether or not, the header is available
        if (isset($this->headers[$name])) {
            return $this->headers[$name];
        }

        // throw an exception, if not
        throw new \InvalidArgumentException(sprintf('Header %s is not available', $name));
    }
Return's the header value for the passed name.

@param string $name The name of the header to return the value for

@return mixed The header value
@throws \InvalidArgumentException Is thrown, if the header with the passed name is NOT available