def to_frequency_domain(self, lower, upper, sampling_frequency, remove_dc=True):
        """Performs the conversion of the Function to the Frequency Domain and
        returns the result. This is done by taking the Fourier transform of the
        Function. The resulting frequency domain is symmetric, i.e., the
        negative frequencies are included as well.

        Parameters
        ----------
        lower : float
            Lower bound of the time range.
        upper : float
            Upper bound of the time range.
        sampling_frequency : float
            Sampling frequency at which to perform the Fourier transform.
        remove_dc : bool, optional
            If True, the DC component is removed from the Fourier transform.

        Returns
        -------
        Function
            The Function in the frequency domain.

        Examples
        --------
        >>> from rocketpy import Function
        >>> import numpy as np
        >>> main_frequency = 10 # Hz
        >>> time = np.linspace(0, 10, 1000)
        >>> signal = np.sin(2 * np.pi * main_frequency * time)
        >>> time_domain = Function(np.array([time, signal]).T)
        >>> frequency_domain = time_domain.to_frequency_domain(
        ...     lower=0, upper=10, sampling_frequency=100
        ... )
        >>> peak_frequencies_index = np.where(frequency_domain[:, 1] > 0.001)
        >>> peak_frequencies = frequency_domain[peak_frequencies_index, 0]
        >>> print(peak_frequencies)
        [[-10.  10.]]
        """